Can't add data to custom extension after delete-insert
I'm extension/mashup developer for my firm and developed 4-5 extensions before without any problem. But in this time i encountered problem.
If I create new sheet and add extension, its all OK. But when I delete and insert same extension or when I insert extension second time to same page I can't add any field to my extension. If I create new sheet, everything is OK. Any change about properties didn't help. Is this bug or do I miss something? I don't know how to approach this problem. I can share my paint codes, properties etc. if needed.
Screenshot: left one is the first time added extension that I added to new page, and right one is the second time added extension to same page. Even if I drag field to extension or choose by clicking add dimension, nothing happens.