Mode: --- ---

Annotation:
Extreme points box mode: Click four times to draw a box. (Use the extreme clicking technique: leftmost, topmost, rightmost, bottommost)
Two-point box mode: Two clicks to define the corners of the bounding box.
Point mode: Single click to define a point
Per-frame mode: Single click anywhere to mark/unmark the frame. (spacebar also works)
Press 'ESC' to abort current box.

Selection:
Hover over boxes/points to select them. Press DEL to delete the selected item. (Selection picks the smallest area box containing the cursor.)

Zooming:
Hold 'z' and draw a two-point box to zoom the view to that box.
Press 'r' to reset zoom state (zoom all the way out)

Image Stack Navigation:
Left/right arrow keys move from frame to frame in the current batch of frames.