pseudoSequential

When building a rocket, sometimes I will select a part to move by accident. This can be especially problematic on larger rockets. Most the times I just place the part and then hit `ctrl+z` but sometimes this just doesn't work, or messes other things up. Is there any way to deselect the current part?

The icon/button I am talking about is located in the upper right of the screen when in flight, and the bottom left of the screen when building. It resembles a wireless icon, and has a little 0 under it, and when moused over it says none. Please help, I am deadly curious and have not been able to find an answer! Thanks!