I thought I knew how to do this, but it turns out I was wrong.
I'd like to position the cursor very accurately on a specific frame and then select an area of the timeline precisely from the position onwards, using the mouse. (The keyboard isn't always convenient except for fairly small areas.)
If I click directly on the cursor itself, this just moves the cursor.
But if I click ever so slightly to one side of the cursor, the selection starts from the NEW position of the mouse and not from the cursor itself.
How do I specify that I'd like the selection to start from the cursor position and not the mouse position?