get rid of confusing regex

services/web/public/coffee/ide/editor/directives/aceEditor/auto-complete/AutoCompleteManager.coffee

@@ -162,7 +162,7 @@ define [
 			cursorPosition = @editor.getCursorPosition()
 			end = change.end
 			{lineUpToCursor, commandFragment} = Helpers.getContext(@editor, end)
-			if lineUpToCursor.match(/.*((?![\\]).|^)%.*/)
+			if (i = lineUpToCursor.indexOf('%') > -1 and lineUpToCursor[i-1] != '\\')
 				return
 			lastCharIsBackslash = lineUpToCursor.slice(-1) == "\\"
 			lastTwoChars = lineUpToCursor.slice(-2)