I recently, on request, added an advanced settings. This allows you to disable some extra parts of GMPC.

You can disable:

• The disable album cover in the player part.
• Hide the favorite icon.
• Disable database, play-queue, search browser, tag based browser, playlist editor, metadata browser and now playing screen.

You can find it under preferences->interface:

Then you click advanced settings, you get a window with check-boxes. You might need to restart gmpc to fully apply the effects.

An example: