"Variable ${selectedText} can not be resolved" when run command search.action.openNewEditor from diff editor

[Binly42]

Issue Type: Bug

The full detail error/warning message is: Variable ${selectedText} can not be resolved. Make sure to have some text selected in the active editor.
And finally not open a new search editor yet.

repro

1. add a keybinding like:

  {
      "key": "ctrl+e ctrl+f",
      "command": "search.action.openNewEditor",
      "args": {
          "query": "${selectedText}",
      },
  },

2. in a normal editor, select some text, emit the shorcut, the command works fine
3. in a diff editor, select some text, emit the shorcut, the result said top above appears
   • no matter select in left side or right side, or even both ...

VS Code version: Code 1.63.2 (899d46d, 2021-12-15T09:40:02.816Z)
OS version: Windows_NT x64 10.0.19043
Restricted Mode: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-8265U CPU @ 1.60GHz (8 x 1800)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: enabled_on video_decode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	7.80GB (0.62GB free)
Process Argv	--crash-reporter-id aef19635-1b79-4f09-9c0d-1ff29d49308d
Screen Reader	yes
VM	50%

Extensions: none

A/B Experiments

vsliv368:30146709
vsreu685:30147344
python383:30185418
vspor879:30202332
vspor708:30202333
vspor363:30204092
pythonvspyl392:30425749
pythontb:30283811
pythonptprofiler:30281270
vsdfh931cf:30280410
vshan820:30294714
vstes263cf:30335440
vscoreces:30384385
pythondataviewer:30285071
vscod805:30301674
pythonvspyt200:30340761
binariesv615:30325510
bridge0708:30335490
bridge0723:30353136
vsaa593cf:30376535
vsc1dst:30424896
pythonvs932:30410667
vscop804:30404766
vscop940:30404999
vsrem710cf:30416617
vsbas813:30426126

[Binly42]

Another point might not related.

From #95582 (comment) , I got that ${selectedText} would throw if there's no selected text.
As a result, currently it is not able to open a search editor, which should be with a complex query based on selectedText (like "query": "foobar${selectedText}",), when not selected anything.

Maybe it is not simple to make the query arg support full-feature snippet.
But it would be great to support when not selected anyting...

IMO it would be more great to support the $0, with that we could easily edit the text to be search when not selected text (by using something like ${0:${selectedText}})

[mjbvz]

@JacksonKearl This works for me when I select text in a normal editor or on the right hand side of a diff view, but not when my selection is on the left hand side (to repro, make sure nothing is selected on the right)