title: CVAT shared annotation for all frames
body: <p>I am new to CVAT annotation tool; I followed the instuction and install it today. When I start my first task and labelling multiple images, after I finished the first one and moved onto the second one, I found the labels are copied to the second image. When I tried to delete those labels, it deleted the labels on the first image. Could you please help me to fix it? Thanks a lot!</p>