Cannot read property 'isReadonly' of undefined

[vscodeerrors]

Issue Id: eebddda3-492c-a040-a071-34e557daa979

Versions
- 1.43.1
Stack
TypeError: Cannot read property 'isReadonly' of undefined
/vs/workbench/browser/contextkeys.ts#226:55 (updateEditorContextKeys)
/vs/workbench/browser/contextkeys.ts#163:71 (call)
/vs/base/common/event.ts#587:15 (fire)
/vs/workbench/services/editor/browser/editorService.ts#139:32 (doHandleActiveEditorChangeEvent)
/vs/workbench/services/editor/browser/editorService.ts#129:7 (handleActiveEditorChange)
/vs/workbench/services/editor/browser/editorService.ts#85:63 (call)
/vs/base/common/event.ts#587:15 (fire)
/vs/workbench/browser/parts/editor/editorPart.ts#595:31 (doSetGroupActive)
/vs/workbench/browser/parts/editor/editorPart.ts#320:7 (activateGroup)
/vs/workbench/browser/parts/editor/editorGroupView.ts#890:17 (doOpenEditor)
/vs/workbench/browser/parts/editor/editorGroupView.ts#822:40 (openEditor)
/vs/workbench/browser/parts/editor/editorDropTarget.ts#271:17
at Object.onDrop (out/vs/workbench/workbench.desktop.main.js

[bpasero]

No real clue how this is possible unless maybe an editor is not playing by the rules of setInput() calls. I have added logging to tell the identifier of the editor that is triggering this.