Tab drag and drop can paste DnD text into other applications that support clipboard text

When dragging a tab into a new window space, the DnD text can be pasted into other applications, if the dragged tab is dropped onto an application supporting text from the clipboard. E.G. If I drag a tab a release it on VSCode or Notepad++ I paste the DnD text into that application. This is problematic as its not always clear that the text has been pasted and the intension is to move the tab to a new frame.

Suggest moving to use a custom data format in the clipboard content to prevent the accidental pasting of the DnD text into other applications.

Start by tracing the tab drag-and-drop path and where its clipboard content is created when a tab is moved into a new window. Reproduce the drop in VSCode or Notepad++ and verify that the tab still moves to a new frame without pasting text into the other application. Done means the drag uses a custom clipboard data format that prevents text pasting.

Written by the indexing model from the issue text.