White rectangle behind Button on hover

[Micron]

Far simpler to set the border property to none as I mentioned?

[Miles R]

Yes, I agree - but having migrated the database to A365 the form should have been converted correctly.
Unfortunately it is a very complex form with multiple tab pages, buttons, images etc etc. Far too much effort to make a new copy of the form from scratch in A365.

[isladogs]

Yes, I agree - but having migrated the database to A365 the form should have been converted correctly.
Unfortunately it is a very complex form with multiple tab pages, buttons, images etc etc. Far too much effort to make a new copy of the form from scratch in A365.

I wasn't suggesting that. It may be sufficient to make a copy of the form in A365.
Or use the exact settings that I did in Form1 on my last attached file

Using a command button with a drop shadow on a tab control with a transparent background on a form originally created in A2007 is a fairly obscure feature.
Perhaps its unrealistic to expect every tiny detail to convert perfectly from such an old version.

Anyway, its your database and your decision