Width override of SizeBox is expected to be just that. 50px is 50px. It ignores this property if the slot alignment is set to “fill horizontally” or if there is no content. Override is also ignored if there is a size specified as slot of a canvas panel.
This is rather annoying when the width override property is used in widget animations.
If you do a hierarchy of
HorizontalBox
|_ Named Slot
|_ SizeBox
Then you can set the named slot to “Fill” and choose Horizontal alignment (for instance center). And set the size box width override and it works.
A bit of a workaround, but I’m getting the vibe that unreal is slowly going down the path of Maya with a 100 methods to jump over bugs atm 
You can also set the proportion of the fill in the named slot and it behaves as it should.
Interesting 
but that would lead to more problems if you need the named slot to be “private” just to get functionality, because you can fill in a named slot from anywhere which is not desired. If the width override property would just work as expected you could make nice “sliding” animations on the width property alone, but it’s too fragile to be used everywhere. Thanks for the testing though you are right unreal is going downhill fast sadly… I mostly post these issues in hopes to get some attention of a quality control team if any exists lol. Worst case EPIC goes the path of Bethesda games, letting the community mop up the issues…
