Xcode odd behaiviour and bad rendering code Recently I'm experiencing some odd behavior from Xcode. It jump up and down on its own, it does not render codes correctly.
Like this screenshot ↓

It's driving me crazy. Have this ever occurred to anybody else?
Is there a solution?
P.S. this problem happens with both Objective-C and Objective-C++ and with every theme I use. (Currently I'm using xcode 6.3)
Turn off the Show live issues checkbox in Xcode > Preferences > General (found near the top of the panel).

I was experiencing the same issue. I found this answer through Editor glitch when editing near end of long file in Apple's Developer Forums. 

It worked for me running Xcode 7.3 with a 2706 line file. The glitch happened around line 2250.