I had a lot of image marks on different layers. I wanted to clear them from one layer, so I right clicked the layer and pressed "clear all image marks". Frankly, I didn't expect it to delete all image marks from all layers. Now here is the saddest part - it cannot be undone...

Going back putting them all again is a lot of work...
I believe this could be somehow fixed to be more intuitive - adding "clear marks from current layer" into the right click menu would really help, and an undo option for this would be also nice, although I understand it might be not easy code-wise. (I know I can delete image marks on one layer from the image marks menu, but it means I have to open this menu each time, or create more shortcut buttons on the interface...)