WOW! That is indeed ugly! On Windows, the same thing looks great.

One thought, is that TCL has a LabelEntry widget, more flexible than Tk's LabEntry. I was thinking that using a widget that combines the Label and the Entry might solve the alignment problem? I couldn't get the Tk LabEntry to do exactly what I wanted, but this can take experimentation.

The TableMatrix I think would solve the issue and be multi-platform, but it would require a bit more work although, I think you can put an entry widget inside of one of the Matrix boxes.

Overall, a nasty problem because Label: Entry would be a normal way one would want to use these widgets.