I have now found out how to reproduce this.

Undock the Address tool bar.
Left-click and hold on the right edge of the Feature combo box arrow,
  as though you were going to resize this combo box wider.
With left button still depressed, move the mouse down and to the
  left, as though you were trying to change the shape of the undocked
  Address tool bar.
Estudio crashes with violation of assertion `not_possible'.