diff --git a/src/main.lua b/src/main.lua
index 348b30a..0745042 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -222,7 +222,7 @@ local keyEvents = {
 }
 
 local function updateEvent(event, ...)
-    if(event=="terminate")then basalt.stop() end
+    if(event=="terminate")then basalt.stop() return end
     if lazyElementsEventHandler(event, ...) then return end
 
     if(mouseEvents[event])then
@@ -272,6 +272,7 @@ end
 --- @vararg any The event to run with
 function basalt.update(...)
     local f = function(...)
+        basalt.isRunning = true
         updateEvent(...)
         renderFrames()
     end
@@ -280,6 +281,7 @@ function basalt.update(...)
         errorManager.header = "Basalt Runtime Error"
         errorManager.error(err)
     end
+    basalt.isRunning = false
 end
 
 --- Stops the Basalt runtime
diff --git a/src/plugins/theme.lua b/src/plugins/theme.lua
index 822d44f..05d7386 100644
--- a/src/plugins/theme.lua
+++ b/src/plugins/theme.lua
@@ -1,3 +1,4 @@
+local errorManager = require("errorManager")
 local defaultTheme = {
     default = {
         background = colors.lightGray,
@@ -160,7 +161,21 @@ function BaseElement:applyTheme()
     local styles = self:getTheme()
     if(styles ~= nil) then
         for prop, value in pairs(styles) do
-            self.set(prop, value)
+            local config = self._properties[prop]
+            if(config)then
+                if((config.type)=="color")then
+                    if(type(value)=="string")then
+                        if(colors[value])then
+                            value = colors[value]
+                        else
+                            errorManager.error("Invalid color '" .. value .. "' for property '" .. prop .. "' in theme for " .. self._values.type)
+                        end
+                    end
+                end
+                self.set(prop, value)
+            else
+                errorManager.error("Invalid property '" .. prop .. "' in theme for " .. self._values.type)
+            end
         end
     end
     return self
@@ -205,6 +220,11 @@ function ThemeAPI.loadTheme(path)
         local content = file.readAll()
         file.close()
         themes.default = textutils.unserializeJSON(content)
+        if not themes.default then
+            errorManager.error("Failed to load theme from " .. path)
+        end
+    else
+        errorManager.error("Could not open theme file: " .. path)
     end
 end