add key bindings to shift label start/end time ±50ms

Is it possible to add key bindings to shift label start/end time ±50ms everytime to current label when it is in focus? Mouse drag is too inconvenient.
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Probably the easiest way at present is:

Moving 50 ms later:

  1. Click on the label track after the last label
  2. “Shift + Home”
  3. “Ctrl+X”
  4. In the “Selection Toolbar”, set the start time to 50ms.
  5. “Ctrl+V”

Moving 50 ms earlier:

  1. Select 50ms in the label track before the first label
  2. “Del”

You could also make these commands into Macros, and set shortcuts to the macros.

When i delete the span of ①,then the label of ② moves to the left, is it possible to keep label 2 fixed?
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Also when i expand the span of ①,then the label of ② moves to the right, is it possible to keep label 2 fixed?
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Is possible to add some extra commands:
drag left boundary of label with a time parameter
drag right boundary of label with a time parameter

I’m not sure what you mean by “the span of ①”.
If you want to only delete “label ①” without affecting “label ②”, Click in the label’s text area and press “Del” (or “backspace”).
For more information, see: Label Tracks - Audacity Manual

I want to only delete or expand the span without affecting label ②.
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Sorry, I means contract or expand Label ① without affecting Lable ② and the others.

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Alternatively, just delete the label and create a new one.

I design some macros and bind keys to them, it works but seems really weird.
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This is better.
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Maybe this is the final version.
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key bindings
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