I have a problem with the UIbuilder

[Controller]

Hello guys,
Im not sure whether this is the right place to post my concern or not but i decided to give it a try.
I tried to modify a recently working maintained.xml file but there is something strange going on. If i load the original file with the uibuilder and change just one very small and unimportant detail like the width of the amountremaining message of frame 10 from 25 to 23 , the whole maintained window will no longer work.
If i save this small change the size of the file changes from 23kb to 29kb.

Is anyone able to give me an advice how to solve the prob ?