I’ve got interesting strange bug in Xcode. I can’t find an information and can’t fix it.
What happened. One day I came into office, and launched the project in XCode (I do not remember the sequence of actions), and instead of a standard keyboard cursor when editing text, I see a flashing white rectangle. The rectangle is similar to the cursor in the operating system DOS. I can not turn it off. The problem has plagued me for a second day.
Take screen shot 
Buttons H, J, K, L perform cursor in the text. Backspace key does not work. Later, after some keystrokes, everything becomes normal, the cursor becomes a standard. After a few seconds, the cursor becomes black again, and everything continues to this scheme.
Additional information:
- Mac mini 2011, OS Mac OSX Lion 10.7.3, XCode 4.3;
- The problem only occurs in XCode;
- The problem occurs with all projects;
- I did not change system settings or XCode;
- This is not a text selection. If you hold the left mouse button, the rectangle appears on the left of the cursor, in the normal state, the cursor is displayed on the right;
- XCode reinstalled several times, with reboots the computer;
- Delete all data in the folder ~ Library/Developer/ and ~/System/Library/Developer;
- Connect other mouse and keyboard;
- I was looking for information on google and stackoverflow.
Thank you for your answer!
I solved this problem.
Deleted XCode. Then I used the program “Find Any File” to search for files containing the title of “xcode” and deleted all files that have been found. Then reinstalled XCode and the problem disappeared.
I tried to find where the settings are XCode but did not find such information, so delete all files containing “xcode” in the title.