Finding myself all too frequently recovering from a train of thought and typing code on the source when I am thinking about the console and vice versa. Sometimes its typing, or trying, into other parts of the layout. After this mistake, and any erasures, I then click where and ought to have been and am get up to speed.
Perhaps if the nice little border around each part of the visible layout could optional, or if defaulted optionally not, have a shading with just a sufficient lack of subtilty that it could be noticed, or sensed without thought, and the cursor retargeted easier than the mess and delay usually made.