• .NET Core Version: All
• Windows version: 1903
• Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes

Problem description:
Triple clicking in a TextBox does not select all text in the TextBox.

Actual behavior:
Triple clicking in a TextBox does not select all text in the TextBox.

Expected behavior:
Triple clicking in a TextBox should select all text.

Minimal repro:

• Create a window containing a TextBox
• Write some text into the TextBox
• Triple click with the mouse