-Fixes Issue 1142. Thanks to carn for the solution to the issue. The tags were being cut off and there were multiple areas of the same tag, so when locating with the tag it gave out unpredictable results.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@5254 316c924e-a436-60f5-8080-3fe189b3f50e

code/controllers/_DynamicAreaLighting_TG.dm

@@ -236,24 +236,24 @@ turf/proc/update_lumcount(amount)
 
 turf/proc/shift_to_subarea()
 	lighting_changed = 0
-
 	var/area/Area = loc
+
 	if(!istype(Area) || !Area.lighting_use_dynamic) return
 
 	// change the turf's area depending on its brightness
 	// restrict light to valid levels
 	var/light = min(max(round(lighting_lumcount,1),0),lighting_controller.lighting_states)
-	//var/new_tag = "[Area.type]sd_L[light]"
 
-	var/new_tag
-	if(length(Area.tag) > 5)
-		new_tag = "[copytext(Area.tag,1,-5)]sd_L[light]"
-	else
-		new_tag = "[Area.type]sd_L[light]"
+	var/find = findtextEx(Area.tag, "sd_L")
+	var/new_tag = copytext(Area.tag, 1, find)
+	new_tag += "sd_L[light]"
 
 	if(Area.tag!=new_tag)	//skip if already in this area
+
 		var/area/A = locate(new_tag)	// find an appropriate area
+
 		if(!A)
+
 			A = new Area.type()    // create area if it wasn't found
 			// replicate vars
 			for(var/V in Area.vars)