This seems to be OS dependent, for me on Linux the drop down is wide enough, even when I reduce the property window to a minimum size.
A workaround should be to extend the property window, then the drop down box should become wider too.
There is a similar issue on 4k displays. The higher DPI on 4k displays messes up many GUI elements.
We already have some open issues on Github for this and I assume that your issue will be solved with that revamp too.
Armin
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