Fix the issues with multiple framelines - For multiple framelines, user move mouse from one frameline to another, the frame is not showed correctly. - Old implementation always draw normal frame on the frameline where mouse just leaving. - It is fixed by detecting leave-notify event and removing hover mark. - When user active a frame on a frameline that is not what old active frame is at, the old active frame is not deactivated. - It is fixed by calling frameline.deactive() of a frameline when a frame is activated on another frameline.