I've been experiencing several issues when editing PDF files in Lumin. I often can't use the Freehand Highlight tool because the page starts flickering. Besides, the PDF content appears to be duplicated/overlapped, with multiple layers of the same page rendered on top of each other, which makes the document impossible to annotate. These issues have occurred repeatedly since last month. Moreover, it would be great if you could add a keyboard shortcut for the Freehand Highlight tool, similar to the shortcuts available for other annotation tools.