diff --git a/coordinator/startup.lua b/coordinator/startup.lua
index 9294633..a3cf6fa 100644
--- a/coordinator/startup.lua
+++ b/coordinator/startup.lua
@@ -22,7 +22,7 @@ local sounder     = require("coordinator.sounder")
 
 local apisessions = require("coordinator.session.apisessions")
 
-local COORDINATOR_VERSION = "v0.21.1"
+local COORDINATOR_VERSION = "v0.21.2"
 
 local println = util.println
 local println_ts = util.println_ts
diff --git a/coordinator/ui/pgi.lua b/coordinator/ui/pgi.lua
index 5e4077f..b603465 100644
--- a/coordinator/ui/pgi.lua
+++ b/coordinator/ui/pgi.lua
@@ -52,6 +52,8 @@ function pgi.delete_pkt_entry(session_id)
         if not success then
             log.error(util.c("PGI: failed to delete PKT entry (", result, ")"), true)
         end
+    else
+        log.debug(util.c("PGI: tried to delete unknown PKT entry ", session_id))
     end
 end
 
diff --git a/graphics/core.lua b/graphics/core.lua
index cff4ff5..534d4e2 100644
--- a/graphics/core.lua
+++ b/graphics/core.lua
@@ -7,7 +7,7 @@ local flasher = require("graphics.flasher")
 
 local core = {}
 
-core.version = "1.0.1"
+core.version = "1.0.2"
 
 core.flasher = flasher
 core.events = events
diff --git a/graphics/element.lua b/graphics/element.lua
index 4630a53..145ee0c 100644
--- a/graphics/element.lua
+++ b/graphics/element.lua
@@ -71,7 +71,8 @@ function element.new(args, child_offset_x, child_offset_y)
         p_window = nil,                                 ---@type table
         position = { x = 1, y = 1 },                    ---@type coordinate_2d
         bounds = { x1 = 1, y1 = 1, x2 = 1, y2 = 1 },    ---@class element_bounds
-        next_y = 1,
+        next_y = 1,                                     -- next child y coordinate
+        next_id = 0,                                    -- next child ID
         subscriptions = {},
         mt = {}
     }
@@ -352,13 +353,14 @@ function element.new(args, child_offset_x, child_offset_y)
 
         local child_element = child.get()
 
-        if key == nil then
-            table.insert(protected.children, child_element)
-            return #protected.children
-        else
-            protected.children[key] = child_element
-            return key
+        local id = key  ---@type string|integer|nil
+        if id == nil then
+            id = self.next_id
+            self.next_id = self.next_id + 1
         end
+
+        protected.children[id] = child_element
+        return id
     end
 
     -- remove a child element
diff --git a/install_manifest.json b/install_manifest.json
index 97287cc..7b7cc96 100644
--- a/install_manifest.json
+++ b/install_manifest.json
@@ -1 +1 @@
-{"versions": {"installer": "v1.7d", "bootloader": "0.2", "comms": "2.1.2", "graphics": "1.0.1", "lockbox": "1.0", "reactor-plc": "v1.5.5", "rtu": "v1.5.4", "supervisor": "v0.20.2", "coordinator": "v0.21.0", "pocket": "alpha-v0.5.2"}, "files": {"system": ["initenv.lua", "startup.lua"], "common": ["scada-common/ppm.lua", "scada-common/comms.lua", "scada-common/psil.lua", "scada-common/rsio.lua", "scada-common/constants.lua", "scada-common/mqueue.lua", "scada-common/tcd.lua", "scada-common/crash.lua", "scada-common/log.lua", "scada-common/types.lua", "scada-common/util.lua", "scada-common/network.lua"], "graphics": ["graphics/element.lua", "graphics/events.lua", "graphics/flasher.lua", "graphics/core.lua", "graphics/elements/listbox.lua", "graphics/elements/textbox.lua", "graphics/elements/displaybox.lua", "graphics/elements/pipenet.lua", "graphics/elements/rectangle.lua", "graphics/elements/div.lua", "graphics/elements/multipane.lua", "graphics/elements/tiling.lua", "graphics/elements/colormap.lua", "graphics/elements/indicators/alight.lua", "graphics/elements/indicators/icon.lua", "graphics/elements/indicators/power.lua", "graphics/elements/indicators/rad.lua", "graphics/elements/indicators/state.lua", "graphics/elements/indicators/light.lua", "graphics/elements/indicators/vbar.lua", "graphics/elements/indicators/led.lua", "graphics/elements/indicators/coremap.lua", "graphics/elements/indicators/data.lua", "graphics/elements/indicators/ledpair.lua", "graphics/elements/indicators/hbar.lua", "graphics/elements/indicators/trilight.lua", "graphics/elements/indicators/ledrgb.lua", "graphics/elements/controls/switch_button.lua", "graphics/elements/controls/spinbox_numeric.lua", "graphics/elements/controls/hazard_button.lua", "graphics/elements/controls/push_button.lua", "graphics/elements/controls/radio_button.lua", "graphics/elements/controls/multi_button.lua", "graphics/elements/controls/tabbar.lua", "graphics/elements/controls/checkbox.lua", "graphics/elements/controls/sidebar.lua", "graphics/elements/animations/waiting.lua"], "lockbox": ["lockbox/init.lua", "lockbox/LICENSE", "lockbox/kdf/pbkdf2.lua", "lockbox/util/bit.lua", "lockbox/util/array.lua", "lockbox/util/stream.lua", "lockbox/util/queue.lua", "lockbox/digest/sha2_224.lua", "lockbox/digest/sha1.lua", "lockbox/digest/sha2_256.lua", "lockbox/digest/md5.lua", "lockbox/mac/hmac.lua"], "reactor-plc": ["reactor-plc/renderer.lua", "reactor-plc/threads.lua", "reactor-plc/databus.lua", "reactor-plc/plc.lua", "reactor-plc/config.lua", "reactor-plc/startup.lua", "reactor-plc/panel/front_panel.lua", "reactor-plc/panel/style.lua"], "rtu": ["rtu/renderer.lua", "rtu/threads.lua", "rtu/rtu.lua", "rtu/databus.lua", "rtu/modbus.lua", "rtu/config.lua", "rtu/startup.lua", "rtu/panel/front_panel.lua", "rtu/panel/style.lua", "rtu/dev/sps_rtu.lua", "rtu/dev/envd_rtu.lua", "rtu/dev/boilerv_rtu.lua", "rtu/dev/redstone_rtu.lua", "rtu/dev/sna_rtu.lua", "rtu/dev/imatrix_rtu.lua", "rtu/dev/dynamicv_rtu.lua", "rtu/dev/turbinev_rtu.lua"], "supervisor": ["supervisor/renderer.lua", "supervisor/databus.lua", "supervisor/supervisor.lua", "supervisor/unit.lua", "supervisor/config.lua", "supervisor/startup.lua", "supervisor/unitlogic.lua", "supervisor/facility.lua", "supervisor/panel/pgi.lua", "supervisor/panel/front_panel.lua", "supervisor/panel/style.lua", "supervisor/panel/components/rtu_entry.lua", "supervisor/panel/components/pdg_entry.lua", "supervisor/session/coordinator.lua", "supervisor/session/svqtypes.lua", "supervisor/session/pocket.lua", "supervisor/session/svsessions.lua", "supervisor/session/rtu.lua", "supervisor/session/plc.lua", "supervisor/session/rsctl.lua", "supervisor/session/rtu/boilerv.lua", "supervisor/session/rtu/dynamicv.lua", "supervisor/session/rtu/txnctrl.lua", "supervisor/session/rtu/unit_session.lua", "supervisor/session/rtu/turbinev.lua", "supervisor/session/rtu/envd.lua", "supervisor/session/rtu/imatrix.lua", "supervisor/session/rtu/sps.lua", "supervisor/session/rtu/qtypes.lua", "supervisor/session/rtu/sna.lua", "supervisor/session/rtu/redstone.lua"], "coordinator": ["coordinator/coordinator.lua", "coordinator/renderer.lua", "coordinator/iocontrol.lua", "coordinator/sounder.lua", "coordinator/config.lua", "coordinator/startup.lua", "coordinator/process.lua", "coordinator/ui/dialog.lua", "coordinator/ui/pgi.lua", "coordinator/ui/style.lua", "coordinator/ui/layout/main_view.lua", "coordinator/ui/layout/unit_view.lua", "coordinator/ui/layout/front_panel.lua", "coordinator/ui/components/reactor.lua", "coordinator/ui/components/pkt_entry.lua", "coordinator/ui/components/process_ctl.lua", "coordinator/ui/components/unit_overview.lua", "coordinator/ui/components/boiler.lua", "coordinator/ui/components/unit_detail.lua", "coordinator/ui/components/imatrix.lua", "coordinator/ui/components/turbine.lua", "coordinator/session/pocket.lua", "coordinator/session/apisessions.lua"], "pocket": ["pocket/pocket.lua", "pocket/renderer.lua", "pocket/config.lua", "pocket/coreio.lua", "pocket/startup.lua", "pocket/ui/main.lua", "pocket/ui/style.lua", "pocket/ui/components/conn_waiting.lua", "pocket/ui/pages/turbine_page.lua", "pocket/ui/pages/reactor_page.lua", "pocket/ui/pages/home_page.lua", "pocket/ui/pages/unit_page.lua", "pocket/ui/pages/boiler_page.lua"]}, "depends": {"reactor-plc": ["system", "common", "graphics", "lockbox"], "rtu": ["system", "common", "graphics", "lockbox"], "supervisor": ["system", "common", "graphics", "lockbox"], "coordinator": ["system", "common", "graphics", "lockbox"], "pocket": ["system", "common", "graphics", "lockbox"]}, "sizes": {"manifest": 5789, "system": 1991, "common": 98474, "graphics": 147714, "lockbox": 34900, "reactor-plc": 95833, "rtu": 105477, "supervisor": 335329, "coordinator": 231949, "pocket": 37639}}
\ No newline at end of file
+{"versions": {"installer": "v1.7d", "bootloader": "0.2", "comms": "2.1.2", "graphics": "1.0.1", "lockbox": "1.0", "reactor-plc": "v1.5.5", "rtu": "v1.5.5", "supervisor": "v0.20.3", "coordinator": "v0.21.1", "pocket": "alpha-v0.5.2"}, "files": {"system": ["initenv.lua", "startup.lua"], "common": ["scada-common/ppm.lua", "scada-common/comms.lua", "scada-common/psil.lua", "scada-common/rsio.lua", "scada-common/constants.lua", "scada-common/mqueue.lua", "scada-common/tcd.lua", "scada-common/crash.lua", "scada-common/log.lua", "scada-common/types.lua", "scada-common/util.lua", "scada-common/network.lua"], "graphics": ["graphics/element.lua", "graphics/events.lua", "graphics/flasher.lua", "graphics/core.lua", "graphics/elements/listbox.lua", "graphics/elements/textbox.lua", "graphics/elements/displaybox.lua", "graphics/elements/pipenet.lua", "graphics/elements/rectangle.lua", "graphics/elements/div.lua", "graphics/elements/multipane.lua", "graphics/elements/tiling.lua", "graphics/elements/colormap.lua", "graphics/elements/indicators/alight.lua", "graphics/elements/indicators/icon.lua", "graphics/elements/indicators/power.lua", "graphics/elements/indicators/rad.lua", "graphics/elements/indicators/state.lua", "graphics/elements/indicators/light.lua", "graphics/elements/indicators/vbar.lua", "graphics/elements/indicators/led.lua", "graphics/elements/indicators/coremap.lua", "graphics/elements/indicators/data.lua", "graphics/elements/indicators/ledpair.lua", "graphics/elements/indicators/hbar.lua", "graphics/elements/indicators/trilight.lua", "graphics/elements/indicators/ledrgb.lua", "graphics/elements/controls/switch_button.lua", "graphics/elements/controls/spinbox_numeric.lua", "graphics/elements/controls/hazard_button.lua", "graphics/elements/controls/push_button.lua", "graphics/elements/controls/radio_button.lua", "graphics/elements/controls/multi_button.lua", "graphics/elements/controls/tabbar.lua", "graphics/elements/controls/checkbox.lua", "graphics/elements/controls/sidebar.lua", "graphics/elements/animations/waiting.lua"], "lockbox": ["lockbox/init.lua", "lockbox/LICENSE", "lockbox/kdf/pbkdf2.lua", "lockbox/util/bit.lua", "lockbox/util/array.lua", "lockbox/util/stream.lua", "lockbox/util/queue.lua", "lockbox/digest/sha2_224.lua", "lockbox/digest/sha1.lua", "lockbox/digest/sha2_256.lua", "lockbox/digest/md5.lua", "lockbox/mac/hmac.lua"], "reactor-plc": ["reactor-plc/renderer.lua", "reactor-plc/threads.lua", "reactor-plc/databus.lua", "reactor-plc/plc.lua", "reactor-plc/config.lua", "reactor-plc/startup.lua", "reactor-plc/panel/front_panel.lua", "reactor-plc/panel/style.lua"], "rtu": ["rtu/renderer.lua", "rtu/threads.lua", "rtu/rtu.lua", "rtu/databus.lua", "rtu/modbus.lua", "rtu/config.lua", "rtu/startup.lua", "rtu/panel/front_panel.lua", "rtu/panel/style.lua", "rtu/dev/sps_rtu.lua", "rtu/dev/envd_rtu.lua", "rtu/dev/boilerv_rtu.lua", "rtu/dev/redstone_rtu.lua", "rtu/dev/sna_rtu.lua", "rtu/dev/imatrix_rtu.lua", "rtu/dev/dynamicv_rtu.lua", "rtu/dev/turbinev_rtu.lua"], "supervisor": ["supervisor/renderer.lua", "supervisor/databus.lua", "supervisor/supervisor.lua", "supervisor/unit.lua", "supervisor/config.lua", "supervisor/startup.lua", "supervisor/unitlogic.lua", "supervisor/facility.lua", "supervisor/panel/pgi.lua", "supervisor/panel/front_panel.lua", "supervisor/panel/style.lua", "supervisor/panel/components/rtu_entry.lua", "supervisor/panel/components/pdg_entry.lua", "supervisor/session/coordinator.lua", "supervisor/session/svqtypes.lua", "supervisor/session/pocket.lua", "supervisor/session/svsessions.lua", "supervisor/session/rtu.lua", "supervisor/session/plc.lua", "supervisor/session/rsctl.lua", "supervisor/session/rtu/boilerv.lua", "supervisor/session/rtu/dynamicv.lua", "supervisor/session/rtu/txnctrl.lua", "supervisor/session/rtu/unit_session.lua", "supervisor/session/rtu/turbinev.lua", "supervisor/session/rtu/envd.lua", "supervisor/session/rtu/imatrix.lua", "supervisor/session/rtu/sps.lua", "supervisor/session/rtu/qtypes.lua", "supervisor/session/rtu/sna.lua", "supervisor/session/rtu/redstone.lua"], "coordinator": ["coordinator/coordinator.lua", "coordinator/renderer.lua", "coordinator/iocontrol.lua", "coordinator/sounder.lua", "coordinator/config.lua", "coordinator/startup.lua", "coordinator/process.lua", "coordinator/ui/dialog.lua", "coordinator/ui/pgi.lua", "coordinator/ui/style.lua", "coordinator/ui/layout/main_view.lua", "coordinator/ui/layout/unit_view.lua", "coordinator/ui/layout/front_panel.lua", "coordinator/ui/components/reactor.lua", "coordinator/ui/components/pkt_entry.lua", "coordinator/ui/components/process_ctl.lua", "coordinator/ui/components/unit_overview.lua", "coordinator/ui/components/boiler.lua", "coordinator/ui/components/unit_detail.lua", "coordinator/ui/components/imatrix.lua", "coordinator/ui/components/turbine.lua", "coordinator/session/pocket.lua", "coordinator/session/apisessions.lua"], "pocket": ["pocket/pocket.lua", "pocket/renderer.lua", "pocket/config.lua", "pocket/coreio.lua", "pocket/startup.lua", "pocket/ui/main.lua", "pocket/ui/style.lua", "pocket/ui/components/conn_waiting.lua", "pocket/ui/pages/turbine_page.lua", "pocket/ui/pages/reactor_page.lua", "pocket/ui/pages/home_page.lua", "pocket/ui/pages/unit_page.lua", "pocket/ui/pages/boiler_page.lua"]}, "depends": {"reactor-plc": ["system", "common", "graphics", "lockbox"], "rtu": ["system", "common", "graphics", "lockbox"], "supervisor": ["system", "common", "graphics", "lockbox"], "coordinator": ["system", "common", "graphics", "lockbox"], "pocket": ["system", "common", "graphics", "lockbox"]}, "sizes": {"manifest": 5789, "system": 1991, "common": 98474, "graphics": 147714, "lockbox": 34900, "reactor-plc": 95833, "rtu": 105774, "supervisor": 335453, "coordinator": 232175, "pocket": 37639}}
\ No newline at end of file
diff --git a/rtu/startup.lua b/rtu/startup.lua
index 9567866..dd1c27f 100644
--- a/rtu/startup.lua
+++ b/rtu/startup.lua
@@ -30,7 +30,7 @@ local sna_rtu      = require("rtu.dev.sna_rtu")
 local sps_rtu      = require("rtu.dev.sps_rtu")
 local turbinev_rtu = require("rtu.dev.turbinev_rtu")
 
-local RTU_VERSION = "v1.5.4"
+local RTU_VERSION = "v1.5.5"
 
 local RTU_UNIT_TYPE = types.RTU_UNIT_TYPE
 local RTU_UNIT_HW_STATE = databus.RTU_UNIT_HW_STATE
diff --git a/rtu/threads.lua b/rtu/threads.lua
index 58d19c6..904f37b 100644
--- a/rtu/threads.lua
+++ b/rtu/threads.lua
@@ -308,7 +308,9 @@ function threads.thread__comms(smem)
 
         -- thread loop
         while true do
-            -- check for messages in the message queue
+            local handle_start = util.time()
+
+            -- check for messages in the message queue while not shut down
             while comms_queue.ready() and not rtu_state.shutdown do
                 local msg = comms_queue.pop()
 
@@ -324,10 +326,16 @@ function threads.thread__comms(smem)
                     end
                 end
 
-                -- quick yield
-                util.nop()
+                -- max 100ms spent processing queue
+                if util.time() - handle_start > 100 then
+                    log.warning("comms thread exceeded 100ms queue process limit")
+                    break
+                end
             end
 
+            -- quick yield
+            util.nop()
+
             -- check for termination request
             if rtu_state.shutdown then
                 rtu_comms.close(rtu_state)
@@ -414,6 +422,12 @@ function threads.thread__unit_comms(smem, unit)
                 util.nop()
             end
 
+            -- check for termination request
+            if rtu_state.shutdown then
+                log.info("rtu unit thread exiting -> " .. short_name)
+                break
+            end
+
             -- check if multiblock is still formed if this is a multiblock
             if unit.is_multiblock and (util.time_ms() - last_f_check > 250) then
                 local is_formed = unit.device.isFormed()
@@ -507,12 +521,6 @@ function threads.thread__unit_comms(smem, unit)
             -- update hw status
             databus.tx_unit_hw_status(unit.uid, unit.hw_state)
 
-            -- check for termination request
-            if rtu_state.shutdown then
-                log.info("rtu unit thread exiting -> " .. short_name)
-                break
-            end
-
             -- delay before next check
             last_update = util.adaptive_delay(COMMS_SLEEP, last_update)
         end
diff --git a/supervisor/panel/pgi.lua b/supervisor/panel/pgi.lua
index 9065f72..dd8b202 100644
--- a/supervisor/panel/pgi.lua
+++ b/supervisor/panel/pgi.lua
@@ -60,6 +60,8 @@ function pgi.delete_rtu_entry(session_id)
         if not success then
             log.error(util.c("PGI: failed to delete RTU entry (", result, ")"), true)
         end
+    else
+        log.debug(util.c("PGI: tried to delete unknown RTU entry ", session_id))
     end
 end
 
@@ -87,6 +89,8 @@ function pgi.delete_pdg_entry(session_id)
         if not success then
             log.error(util.c("PGI: failed to delete PDG entry (", result, ")"), true)
         end
+    else
+        log.debug(util.c("PGI: tried to delete unknown PDG entry ", session_id))
     end
 end
 
diff --git a/supervisor/startup.lua b/supervisor/startup.lua
index 123ba21..59f5c4f 100644
--- a/supervisor/startup.lua
+++ b/supervisor/startup.lua
@@ -21,7 +21,7 @@ local supervisor = require("supervisor.supervisor")
 
 local svsessions = require("supervisor.session.svsessions")
 
-local SUPERVISOR_VERSION = "v0.20.3"
+local SUPERVISOR_VERSION = "v0.20.4"
 
 local println = util.println
 local println_ts = util.println_ts