Question Strange transparent window, What is this?

[Hefciuu]

Hello, yesterday I discovered something strange when i was watching youtube some strange white window appeared on my second monitor in left bottom corner, I tried to discover whats that but it ended alf+f4 and it dissapered. For a while I had issues with for example running some apps from my windows bar like some transparent window would block it. Same today it appeard on windows start on second monitor in the left bottom corner I can move it but i have no idea how to discover whats that, so i think that app or whatever it is was working for a while and the only way that I could find out that it is there in the background it was that moment that window went white and I could actually see it.
Here's video showing what I mean :

View: https://youtu.be/DeZUEtqii1E

 

[britechguy]

All I can see in that video is an instance of the standard Windows desktop "multi-select" enclosure showing up. If this is happening without your having held down your left mouse button when getting it then I suspect something's going wonky with your mouse.

You can stretch this window to surround whatever desktop icons you wish and after releasing the left mouse button all will be selected.

Very few of us use this at all, let alone with any frequency, but it's not new.

 

[Hefciuu]

What I meant, look on the video when im moving mouse on the icons, icons light up and when I move my mouse to that transparent window icons don't light up and I can't click on them like some window would block it, same on the main screen when im trying to hold left mouse button and select some files its not working cuz some window blocks it, app or whatever thats it its just transparent window thats blocking any action and u can see that that blue window when u are trying to select multiple files not showing up also. Yes I know how it looks like but its really hard to find that window and i have to click on every single point on my screen, just trust me there is something im sure and the question is how to find out whats that.

 

[britechguy]

You'll get my standard advice set when dealing with a Windows 10 system that is acting quirky, but where an infection has been ruled out as the cause:

Before going any further, it must be noted that a repair install (or feature update, when those are being done) allows one to keep all of one's files and apps (desktop/installed and store varieties). This is in complete contrast to a Reset (which allows either keeping just one’s files or wiping everything), or a Refresh/Fresh Start or Completely Clean Reinstall, both of which wipe everything.

My standard advice, in virtually all cases, (and presuming any potential infection has already been addressed, first) is trying the following, in the order specified. If the issue is fixed by option one then there's no need to go further. Stop whenever your issue is fixed:

1. Using SFC (System File Checker) and DISM (Deployment Imaging Servicing and Management) to Repair Windows 8 & 10


2. Doing a Windows 10 Repair Install or Feature Update Using the Windows 10 ISO file


3. Doing a completely clean reinstall (options a & b are downloadable PDF files):

a) Completely Clean Win10 (Re)install Using MCT to Download Win10 ISO File

b) Completely Clean Win10 (Re)install Using MCT to Create a Bootable USB Drive

c) How to do a CLEAN Installation of Windows 10 (Tom’s Hardware Forums, with screen shots)

I never choose the “thermonuclear option,” the completely clean reinstall, until it's clear that this is the only viable option. I hate having to go through all the work of reconfiguring a machine from scratch if that can reasonably and safely be avoided.