Hi Nikita, if you hold down Shift+Ctrl that will force a selection window no matter where you click so you don't need a blank spot to start the window select.

Then also you would want to start the selection on the left side and drag towards the right. That will make a window that will only select things that are completely inside the selection window.

If you start on the right and drag towards the left that will make a dashed "crossing window" that will target anything that intersects the window even partially.

In general though if there is a lot of stuff getting in your way and you're having difficulty selecting some particular object that usually means you need to be hiding things to simplify your working environment so you don't have so much stuff being displayed all at once.

If you are still having trouble making a particular selection can you please post the .3dm model file so I can take a look and maybe give some suggestions on that specific case?

- Michael