The Lumetri Curves Graph sometimes stops 'working' (can't move the lines on the graph) when using in the essential workflow. Only fix is to switch to colour workspace

When in the Essentials workspace, in the Lumetri Colour Panel on the rightside, there are times when I am using the Curves Graph and it just stops allowing me to make changes. My mouse can’t grab onto the graph. The only way to continue editing is to swtich to the colour workspace.