So I finally got it working on Android and Win64. Here are my changes taken from SiverWarrior and Dave.
The last tweaks have been to use Skia, otherwise the tab' slants are drawn over the menu. Also I hat to choose "BringToFront" on the TListBox on the form. It did not work at structure view of the object inspector as the "BringToFront" menu option of the context menu is disabled there. Thank you!