This seems to be the result of some customization or third-party plugin.
Could you try the approaches below?
1) Try resetting the custom decorator from Administration >> Layouts or Browse >> Space Admin >> Layouts.
2) If the approach below do not help, try to set your Confluence Plugins on "Safe Mode" and check if the behavior persists;
Just a quick note about this bug. The issue is resolved in Confluence 5.1.3.
If you are on a version of Confluene pre 5.1.3 we have a plugin fix for this editor height issue available in our marketplace.
Hi team, I’m Avinoam, a product manager on Confluence Cloud, and today I’m really excited to let the Community know that all customers can now try out the new editing experience and see some of the ...
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG
You're one step closer to meeting fellow Atlassian users at your local meet up. Learn more about AUGs