Ok, here's the thing - I keep loosing the ability to draw on the canvas (Lascaux Sketch). I know I must be forgetting to do something but . . . I think the first time it happened was after I made a selection - I couldn't get 'out' of it. I had to draw another selection over the whole canvas to get anything to work . . . These are just the times I remember what I was doing, there have been others - it there a toggle switch, or a 'return to normal' button. Am I alone with this problem?
If anyone can shed some light on this quirk I'd love to hear from you.

ctrl + d removes the selection.

thanks