Every now and then when there is a storm in Creative Mode the letter "A" cannot be typed. When the letter "A" is typed whatever is typed before gets highlighted. White in the text bar and blue in inventory search.
Screenshot 1: Trying to type "/weather clear"
Screenshot 2: Trying to type "wall"
Environment
Operating System: Mac OS X (x86_64) version 10.9.4
Java Version: 1.6.0_65, Apple Inc.
You're pressing CTRL at the same time : CTRL-A -> Mark all