[SOLVED] Ubuntu 18.04 Bionic Beaver: some small annoiances

Hi All,
Having nostalgia after long time I have been installing Ubuntu again but Am experiencing some annoiances and hoping you know how to fix them.
I write down all here thinking is a nonsense to open single discussion for each one, so:
1 - I have been installing some GNOME Extensions, one of them does’nt work so I removed it ( no more listed on my page “Installed Extensions”), on the application’s page comes out as “OFF”. It is:
Applications Menu
by fmuellner
It is still on the bar and I don’t know how to get rid of it (the second one, the first one added later works), adding a pic showing you what I mean:
2 - Can’t install downloaded themes, as for single user as putting the files on /usr/share/themes I have been trying with the following themes:

3 - Nautilus showing the folder “snap”: can I rename as .snap or Snap without inconveniences?
Adding a pic showing it:
4 - Click dx on file, we have “Move to trash”, is possible to add “Delete”? If “yes”, how?
Thank you for your attention,

Point 1: - SOLVED - ( removed the apps’ folder in the path /usr/share/gnome-shell/extensions/ )
Point 2: - SOLVED - ( my fault, I was using themes not compatible with Gnome-Shell version )
Point 3: apparently that is a bug not fixed till now
Point 4 - SOLVED - ( my fault, when setting up Nautilus I did’nt see the line activating that service )