Within ARCON 3D, there are a number of objects which you may find that once placed, cannot be selected again to edit, move or delete (eg. dimensions, windows etc).

This is because, in default mode not all object types are selectable. This is however, fully customisable to suit your own requirements.

Using the menus, navigate to:

Options > Program > Snap and Select > In Construction Mode...
(shortcut CTRL + Spacebar)

Select the 'Selectable Elements' tab. You will see a variety of object types. Ensure those you require are ticked and press 'OK'.