Cannot place cursor and cannor expand effects options

Hello,

I have a strange problem with Premiere Pro that started today. As I add the first clip, everything is fine. But as soon as I add another one, all goes bad:

1) I cannot move the cursor in the timeline anymore - so  I cannot place it in some particular moment to cut the clip or whaterer

2) In the Effects options window I cannot open any command, no Motion, no opacity, no Volume options dont open anymore, nothing --  I cannot twirl it.

RAM 8G, Windows 10, Premiere Pro CC 2018

I reinstalled Premiere Pro, it didn't help. What the matter and how to fix it?

Thanks