BUG: Panel UI problem.

[hiroshisaito]

Describe the bug
Old panel instances remain when switching views within a tab.

To Reproduce

1. Open any panel as a tab.
2. Switch to a different view (e.g., Media) using the tab's view-switching menu (chevron), or switch that plugin panel to a different view.
3. Repeating the operation in 'Step 2' causes the rendering content of the previous panel to remain visible in the pane (it disappears when the tab is closed).

Desktop (please complete the following information):

• Rocky Linux 9.7 / xSTUDIO 1.3.0