Yep, I also was able to reproduce it here setting my scaling to 300%.
That gets back to my original theory and something I have also tested out with my toolbar problem mentioned in the other thread - it’s definitely a Rhino UI programming problem, when the dialog box exceeds a certain fixed number of screen pixels, this occurs. So increasing the display scaling makes the dialog occupy more screen pixels, and when it “hits the wall” of that hard pixel count, the problem happens.
As the Selection filter is set to ‘snap’ to fixed column and row widths, I don’t know where this actually occurs, it’s fine at 250% scaling and goes wonky at 300%.
After more tests the "wall’ seems to be at a column width of 300 pixels or more.
At 250% scaling on my 4K screen the single column selection filter dialog box here is 284 pixels wide and displays OK - below are the full the results in a table:
250% - 284 px - OK
260% - 290 px - OK
270% - 300 px - OK
275% - 305 px - Bad
280% - 312 px - Bad
300% - 335 px - Bad
Voilà… The toolbar problem is similar, the limit seems to be pretty close, at around 294 pixels.