Remove stones from game
While recording game, one easily stores extra moves that were not actually played.
Any extra moves can be delete at any time they are visible in the board.
When you want to delete move, first select it by clicking it with right mouse button. This
creates red circle around the selected move. Then press delete move(s) button 
.
If you want to delete several moves at once, you can select them one by one. First move is
selected as above and other moves are selected by keeping shift pressed and then selecting
additional moves with right mouse clicks. All selected moves should have red circles around
them. When you have selcted all stones you want, you can delete them with delete moves
button .
Move stones in board
Often one finds that certain move is in wrong place, and should be corrected. Of course this could be corrected by first deleting move in wrong position and then adding new move to correct position. However there more natural way to correct situation.
Stones can be moved in the board only when general 
or move editing tools 
are selected. If
another tool is selected (buttons in left side in window), you should start by chaging to
general or move editing tool.
Move positions can be moved in board when they are visible in the board. First select move by right mouse button. Then you can draw move to new position with right mouse button.
Alternative, faster way to move single stone is by pressing right mouse button on top of move and directly after this dragging move to new position. This combines selection of move and dragging it to new position.