Currently clicking in the terminal will cause a blur on mousedown and a focus on mouseup (provided there is no selection). This results in the cursor showing a non-focused state even though technically the terminal is still focused and keyboard input will go to the shell.

Notice the selection and the cursor state:

We should put a layer in between the browser textarea blur/focus events and expose our own events, that way we can cover these mouse-related edge cases without affecting the cursor state.