If OnMouseButtonDown is unhandled, there is no way to detect a left-click on the widget.

Summary

The IsMouseButtonDown mouse event ceases to function if OnMouseButtonDown is left unhandled. Additionally, if the mouse cursor is over the widget, IsInputKeyDown stops working for left-clicks. Due to these factors, there is no way to detect a left-click on the widget when OnMouseButtonDown is unhandled.
This causes limitations or issues with left-click usage in widgets that are used in a stacked manner, such as those within list views or slots.

What Type of Bug are you experiencing?

Editor

Steps to Reproduce

1.Connect “Unhandled” to the return node of OnMouseButtonDown.
2.And then you realize that you can no longer use left-click with that widget.

Expected Result

Even in the Unhandled state, there is a way to use the left click, just as in the Handled state.

Observed Result

This makes it unusable because it eliminates the way to detect left clicks in branching.

Affects Versions

5.8

Platform(s)

Windows

Additional Notes

From what I’ve briefly looked into, it appears to be an issue that has been left unaddressed for years.