GGU-CAD: Changing the sequence of objects
The objects are displayed on the screen in the sequence in which they were drawn. This can lead to certain objects being hidden by colour fills or graphics hatching. To move a colour-fill to the background, for example, so that other objects are not hidden, go to the menu item "Draw/Edit object" or press [F3] and click the colour fill.

Then activate the "To back" check box in the dialog box and confirm with "OK". The colour fill is then drawn first. Alternatively, it is possible to click hidden objects and bring them forwards.