NGUI button stops working after file is saved

[jcsl]

I am having a really weird problem. I have four buttons in an Android game, horizontally aligned. 3 of them work well, but the fourth, which is located on the left side of the screen, only works if it is placed vertically above the other 3 buttons. If I place any of the other 3 buttons on the left side of the screen, they work without a problem. If I place the problematic button in any of the other 3 positions, it still doesn't work.

I have recreated the problematic button from scratch 10 times. It works without a problem, then I close the program and when I open the file it is not working again. There is nothing overlapping the button, and there is only a background behind it. I have checked for depth conflicts and there are none.

I would greatly appreciate if anyone can tell me why this is happening.

Thanks!

[ArenMook]

My guess is that you chose 3D World event type on your UI camera instead of the 3D UI, and you have some other collider in the same place. Turning on Debug on the UICamera will show you what it's hovering over.