Capture programs like HyperSnap allow keyboard control of capture area as follows:
1. Using SHIFT key to move in 10-pixel jumps
2. ENTER key to accept the top-left position
3. ENTER again to accept bottom-right position (complete capture)
4. TAB key to swap between top-left and bottom-right positioning
Currently Greenshot keyboard implementation in captures is pointless, as it requires a mouse-click to accept the position chosen by keyboard. Pressing ENTER does nothing. Mouse button has to be held down while using keyboard to move the second position, which is completely silly.
Please allow proper keyboard usage during capture, as often a pixel-precise capture is needed for serious usage.