Markers viewlet goes empty when being dragged

[jrieken]

while verifying #94530

Screen Recording 2020-04-28 at 15.41.37.mov.zip

• see attached recording 🔝
• show markers
• have file with errors
• drag marker to sidebar
• drag back to bottom panel
• 🐛 panel is empty, content is gone

[sbatten]

okay, this is the third issue around moving a default view container to and from the sidebar causing issues. have a feeling there is a singular issue in the moving view containers logic.

[sandy081]

Looks like panel composite is not removed on deregister - https://github.com/microsoft/vscode/blob/master/src/vs/workbench/browser/parts/panel/panelPart.ts#L225

Hence ViewPaneContainer.create is not called when view container is moved back to panel.