I have found the following three issues:

1) that can also be reproduced on Windows, but it is easier to reproduce them on Linux

• uncheck the "Hide Installed" checkbox
• select all (or some installed and uninstalled) connectors

If you are fast enough, you will be able to click both, the Install/Update and Uninstall button that will open the Install and Uninstall dialog

2)

• uncheck the "Hide Installed" checkbox
• click "Select all"
• enter some filter (m2e, for instance)
• click "Unselect all"

Some of the connectors (hidden) will remain selected.

3)

• collapse the "Features Available" section

You will see a big empty area between the "Features Available" and "Early Access Features" section.