Questions[mate](ubuntu)

I have a weired sympton with a fresh Windos 10 guest OS under VirtualBox 5.1.28 under Ubutunu-MATE 16.04:

I can't move the window at all, when [x] Auto Capture Keyboard is on.

Neither dragging the outer windows borders (resize), nor the titlebar (indeed just move the virtuabl box. So this is not about auto-resize on or off...). If I deactivate the option, things work fine again. (I do not even understand the relation). – sounds like a virtual box bug? Can't reproduce the opposite, but I have been working with virtual box (and Win7 guests) for long, never encountered this until 2 weeks ago.

But then, common shortcuts I have defined in host and guest, don't work on the guest but rather the host (i.e. WIN-R to get a run programm...). So, of course capturing is desirable.

I have a doubt, there is a free program to share mouse between linux and windows, I have a PC and a laptop, on the laptop I have w10 and ubuntu mate 18.04, and the pc w10, when I use the PC and laptop with w10, I use the windows software called "Mouse without borders" but it is only for windows, I am looking for a free one for linux and windows, I know that there is sinergy but it is paid

Just noticed this annoying emoji input ("Emoji Choice") popping up every time I press Ctrl+Shift+E in 18.04. I really need this shortcut to switch to the file explorer in Visual Studio Code but instead I only get the emoji input. Is there a way to disable this or at least change the shortcut? Don't want to change the VCS's shortcut because of this, I'm really used to it

I find it odd that in the year 2015, there is still a problem with operating systems not dealing correctly with higher DPI values. So if the resolution is high for the same screen size, all fonts, icons, panels, windows etc. will be relatively too small, and sometimes just tiny.

It seems that there may be a partial solution for that in Unity, but I am using the Mate desktop. Is there a way to just scale everything up so it is bigger - fonts, icons, panels etc?

My resolution is 2880x1620 on a 15 inch monitor and everything is so tiny it is completely impossible to use. I could decrease the screen resolution, but the alternative, lower resolution lead to different aspect ratios, thus distorting everything. It also seems wrong to lower the resolution just to fix this, instead of the OS scaling the size up at the higher resolution, which should show better, more crisp graphics and fonts.

I understand MATE is a desktop environment, but what is the difference between ubuntu with a MATE desktop environment and ubuntu-mate ?

EDIT: Difference Between Ubuntu and Ubuntu-Gnome is not a duplicate of my question because there is a dedicated distribution called ubuntu-mate