Clicking on it can cause some navigational issues, due to the camera zoom-in.
Click controls DO work about 85% of the time, but due to the nature of some of the events and cameras and things in our game, we can't promise they work all of the time. Just some limits of the engine we can't overcome.
You should be able to go up to it using regular arrow key movement. And also double-check you're on the latest hotfix v0.307 as opening the chest from the side can sometimes cause you to get stuck too.