Add SelectTextOnFocusBehavior to automatically select the content of a TextBox when it is focused.

[vgromfeld]

Fixes

Add a new SelectTextOnFocusBehavior to automatically select the content of a TextBox when it is focused.

PR Type

What kind of change does this PR introduce?

• New behavior for TextBox controls

What is the new behavior?

I'm adding a new behavior which will can be attached to TextBox controls. This behavior will automatically select the TextBox content when the control receives the focus.

PR Checklist

Please check if your PR fulfills the following requirements:

• Created a feature/dev branch in your fork (vs. submitting directly from a commit on main)
• Based off latest main branch of toolkit
• Tested code with current supported SDKs
• New component
  • Documentation has been added
  • Sample in sample app has been added
  • Analyzers are passing for documentation and samples
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• Tests for the changes have been added (if applicable)
• Header has been added to all new source files
• Contains NO breaking changes

Other information

I'm also updating the slngen dependency to the latest available version to allow it to run on ARM64 devices.