Close button on tabs missing

[peter76]

Describe the bug
The close button ( x ) for a tab is missing. When I double click a file it opens in a new window ( see other bug ) and for a brief moment I can see the X but it disappears and doesn't get back.

Desktop (please complete the following information):

• OS: Fedora 34
• Version: 2.0.0-rc2

[peter76]

Sorry, marking this as closed, thinking in VS Code, but now seeing the ide opens an Arduino project as the old ide.