I noticed that after i took a ship out of the fleet. I sold the ship. After that i tried to delete the fleet but i wasn't able to click anything on the whole page! This is either a bug or it just might be my computer. I'm not sure.

Most probably your computer. If it happened one time only, it might have been a simple freeze.

If you get it to other pages too, check for a 3rd party extension/addon in your browser. Best disable them all and then enable one by one to see what is causing it.