[Enhancement] Simulate drag-and-drop of non-tab items (e.g. URL text) onto the "new tab" button

[piroor]

Abstract

Firefox opens a new tab at the end of the tab bar, when you drag a URL text onto the "new tab" button. TST should simulate the behavior.

Steps to see the situation

1. Install TST.
2. Open the sidebar panel.
3. Start dragging of a link to a website.
4. Drop the link to the "new tab" button in the sidebar panel.

Expected result

The dropped URL is opened in a new tab.

Actual (present) result

We cannot drop URL onto the "new tab" button.

Environment

• Platform (OS): Windows 11
• Version of Firefox: 133
• Version (or revision) of Tree Style Tab: 4.0.25

[piroor]

Done by 2942e77