"On Mouse Button Up" doesn't work the first time

I have a situation where I need to use “On Mouse Button Down” and “On Mouse Button Up” on a widget. “On Mouse Button Down” triggers every time as expected. However “On Mouse Button Up” doesn’t trigger the first time if the previous mouse click was outside of the widget or the widget’s parent. It triggers for the second and following clicks as expected. If I click away and try again, it again ignores the first click and triggers on the second while “On Mouse Button Down” triggers on every click.

Has anyone seen this behaviour? Please let me know if you need visuals if I’m not making sense.

This is a standard, albeit somewhat frustrating behaviour. The widget is unaware the button went down, up won’t trigger.

Apart from using Input Mode UI Only, not sure if this can be handled in BPs.


Buttons handle it, kind of:

But this can cause other unwanted behaviours.


There is something you could try:

Have the standard up / down overrides but also add the above.

This onMouseEnter will not trigger immediately but only when a pressed mouse button is released. Hacky but may work well enough with some extra conditionals set up.

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Wow…that Set User Focus worked…for some reason… Thanks!

It’s complaining with warnings, but it works.

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