After defining the extend of my printed map in the printcomposer I can show the map center in the canvas by hitting "view extend in map canvas". So far so good. But is it also possible to show the exact extend with all borders? Or even better: map composer extend is shown as rectangle in the canvas.
At the moment I get that result by copying the coordinates of the map-composer extend to a txt-file (;-sparated), import it to the canvas and connect the points as polygon. But if I change the extend of the print composers map, I have to do all steps again. So is there a other way?