better wirer behavior etc

world.lua

@@ -429,13 +429,16 @@ function World:resolveCircuits()
 				local position = {x = x, y = y}
 				local key = cellKey(position)
 				local tracks = self.wireMatrix[y] and self.wireMatrix[y][x]
-				local runCount, powered = 0, tracks ~= nil
+				-- A circuit can be started with a click before the author drags its
+				-- first segment.  Those zero-length fragments are not a completed
+				-- electrical run, so they must not permanently lock a door that also
+				-- has real door-to-switch routes.  Only valid components participate
+				-- in the door's AND condition.
+				local runCount, powered = 0, true
 				for circuitId in pairs(tracks or {}) do
-					runCount = runCount + 1
 					local component = components[circuitId] and components[circuitId][key]
-					if not component or not component.valid then
-						powered = false
-					else
+					if component and component.valid then
+						runCount = runCount + 1
 						for switch in pairs(component.switches) do
 							if not switchPressed[switch] then powered = false end
 						end
@@ -676,7 +679,35 @@ end
 
 function World:switchPlayerColor(room, color)
 	local player = room.player[color]
-	if not player then return false end
+	if not player then
+		-- A colour copy can be parked in another world room.  Number keys are a
+		-- direct way to resume controlling it: keep every copy where it is, but
+		-- make its owner the active room and select that colour there.
+		local destination
+		for name, candidate in pairs(self.levels or {}) do
+			if self:roomLocation(name) and candidate.player[color] then
+				destination = candidate
+				break
+			end
+		end
+		if not destination then return false end
+
+		for _, possibleColor in ipairs(room:getPossibleColors()) do
+			room:setActiveColor(possibleColor, false)
+		end
+		for _, possibleColor in ipairs(destination:getPossibleColors()) do
+			destination:setActiveColor(possibleColor, possibleColor == color)
+		end
+
+		currentRoom = destination
+		self.lastRoom = destination.name
+		destination.player[color]:playSwitchSound(true)
+		self:markDirty(room)
+		self:markDirty(destination)
+		self:flushRuntime()
+		setEditorRoomName(destination.name)
+		return true
+	end
 	local activeColors = room:getActiveColors()
 	local canSwitch = #activeColors ~= 1 or activeColors[1] ~= color
 	if canSwitch then