[KevinH]

And I have no issues like that on my platform. So this is something specific to your setup and probably has something to do with drag distance, or you holding your mouse button down overly long and not releasing it until after you have started your move. etc.

You can increase the drag distance to prevent something becoming a drag until you click and hold on it and move far enough away. Check out the Sigil User Guide.

See the Advanced Topics chapter:

Use the environment variable:

SIGIL_DRAG_DISTANCE_TWEAK

This environment variable is Windows Only. You can set this to change the distance in pixels needed to move something before drag and drop is detected by the system. Its valid values range from -20 to 20 pixels.