Edgar wrote:as far as I can tell it is impossible to make a selection and then click somewhere within it to set the cursor – the selection goes away.
That's correct, though with two exceptions:
"Edit menu > Region Save/Region Restore"
and "Edit menu > Region Lock".
However, "Play to/from the current pointer position to/from the start/end of the selection" with the "B" key does not use either of these features. It plays from the "pointer" position (without clicking on the track). See "Play to selection" here: http://manual.audacityteam.org/index.ph ... _Recording