Whenever I accidently click outside or near the edge of the window the pause menu appears. When I click resume I start moving towards the middle of the screen because this is where my mouse cursor is. Tried checking is the Resume-option was accepting Space as input, but that didn't work. Moving towards the middle sometimes forces you into some unfavorable positions.
Just click the floor below where you clicked the vase to drop it and break it. There's no obvious spot on the ground you need to click. Just move your mouse over the floorboards and eventually the pointer will change to where you need to click to drop the vase :)