Fix inaccurate text reporting in Visual Studio text controls

[LeonarddeR]

Link to issue number:

follow up of #14888

Summary of the issue:

During development of #14888, it was observed that XAML edit fields tend to fire text change events before the caret position is changed, resulting in wrong text reporting. After using Visual Studio, I discovered that the same issue applies to the text controls in Visual Studio, notably WPF.

Description of user facing changes

In Visual Studio, the caret position is no longer sometimes reported inaccurately.

Description of development approach

use a common base class for XAML and WPF editable text.

Testing strategy:

Tested that caret reporting is again accurate in Visual Studio.

Known issues with pull request:

None known

Code Review Checklist:

• Documentation:
  • Change log entry
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• API is compatible with existing add-ons.
• Security precautions taken.

[seanbudd]

Thanks @LeonarddeR

[seanbudd]

Is this a regression fix? should there be a change log entry?

[LeonarddeR]

It indeed fixes a regression caused by the new UIA implementation in 14888, so a changelog entry shouldn't be needed.