I have placed the Image component below the Button component, when I try to use horizontal fill for the Image component, I found that the left and right sides are not filled but there is a gap, this problem was found in UE5.1 version, I tried in UE4.27 version and found that there is no such problem, I would like to ask you all how to solve this problem in UE5, thank you!
UE5：
UE4：
At a glance this appears to be a bug. There’s been some regression in UMG.
Does it also manifest with another native widget, like a border?
If so, then my advice would be to get the latest engine version.
See below → weird default button padding.
Version 5.3 has the same problem! It’s hard. 
Is the button modified in any way?
edit: so yeah, this seems to be a standard behaviour now, which does not seem right, indeed.
edit2: found it:
You can set it to 0 or a non-0 value. But 12 would mean 12px from each side.
I had this issue and the above post solved it! Thank you! I was about to rip my hair out!
