You can select an individual handle on a frame, and you can switch between having a handle selected and having the whole frame selected.
Prerequisite
Frames
is selected in the Engrave toolbox.
Procedure
In Engrave mode, select a frame handle in any of the following ways:
Select any handle on the frame and press Right Arrow/Left Arrow/Up Arrow/Down Arrow to select other handles around the edge of the frame.
Select the frame, press Tab to switch to having the handle in the top left corner selected, then press Right Arrow/Left Arrow/Up Arrow/Down Arrow to select other handles around its edge.
Click a handle on the frame.
Note
You can only select a single handle on a single frame at a time.
Optional: To switch back to having the whole frame selected, press Tab.