@wangwei1073 When the tabs are on the side, the Windows Title bar is not available for dragging. (When it is on top, the Tab Bar is merged with the Title Bar.
When the Tab Bar is on the side, go to Settings, Appearance, and enable:
Show Title BarOtherwise, use the Windows Shortcut Alt+Spacebar followed by the access key M to get the four way cursor for moving windows.