Hi @Jayanne.Sung,   This is a symptom of  https://gitea.wildfiregames.com/0ad/0ad/issues/8611  TLDR : Most likely you have the bug where the cursor is not pointing where it should be. Try to restart the game until the black margin doesn't appear. Maybe someone else know a way to open the game that will increase the chances to not have this bug (without disabling full screen that is) ? For me the bug happens 1 time out of 20 or so, therefore I usually just restart the game.

I guess I never got that memo... 

I should add that tabbing doesn't cycle though the button on the screen so I can't clear the welcome screen notification and click the ok button so I am stuck. App is full screen however there is a large 4cm black border along the top margin. I can see the left menu and there is a box "Help 0 a.d." in the bottom right corner which is not cut off but I can't click on the "Enable feedback or Terms" button either. I can scroll the mouse fully around to all parts of the screen but none of the buttons are clickable.

First time trying to play the game. Appimage downloaded and run. The game starts and the welcome screen is displayed: "Thank you for installing 0 A.D." The mouse is responsive however none of the buttons are clickable. I can't click on OK to clear the welcome screen and access the menu so I am stuck. All I can do it terminate the process. System: Kubuntu 25.10 Build: February 6, 2026 (release 0.28, ac2cae)

That's not even playing, that's try-harding. And you can't try-hard this game and marvel at its beauty at the same time.  One of the reasons why all first "try-hard" esport RTS games didn't have awesomene graphics. At some point, developers said: enough fluff, let's focus on gameplay.