Selecting data
A-B select
Click somewhere in a view to set the cursor to that location.
You can then press shift+1 in View mode to set the A point of a selection,
and shift+2 to set the B point of a selection.
Once you have both an A and a B point, the selection is the region spanning
A and B.
Select all
You can select everything in a view with Edit->Select all in view or Ctrl+A.
Mouse drag selection
Click a byte and drag the mouse, releasing it when the desired region is selected.
Mouse block multi-selection
Hold down left Alt and draw a rectangle with the mouse to select a block.
Unselecting
You can press the clear button in the top bar, or press Esc.
