Thanks for your feedbacks. [:)]

Constrain the scaling line to horizontal by holding the SHFT or CTRL key?

I added an horizontal/vertical constraint when SHIFT key is pressed in the Beta 11, but won't go further at this time.

on a WinPC CTRL-ScrollWheel does not zoom in this window.

Maybe it will in a future version, but not in 4.2.

And in the 2d window, CTRL-ScrollWheel also does not work when drawing walls or rooms. But this is not new to sh3d 4.2)

Yes, it's on purpose, otherwise there are some cases where the current point of the drawn wall/room would jump weirdly.

With the possibility to create advanced windows and doors, it is very tempting to add lightsource to a door window (or in wall aquarium ). But I didn't manage on a door/window (lightsource properties disappears).

Interesting case... Never thought about this! [;)]
But doors and windows are treated differently from lights at the moment, and lights specified for a door will be simply ignored.