The keyboard mode selector shortcuts used in the piano and automation editor currently are:
SHIFT+d - draw mode
SHIFT+e - erase mode
SHIFT+s - select mode
SHIFT+m - move mode
The first 3 key combos are all easily done with just your left hand, its only for SHIFT+M that you have to use your right hand, which is why I think LMMS would gain much usability by changing the move keyboard shortcut to SHIFT+a and hence changing the name of the function to 'Adjust Position'