Description
- .NET Core Version: 4.7.1+
- Windows version: (
winver): RS1+ - Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes
Problem description:
WPF uses direct calls to InputPane.TryShow via TipTsfHelper when the focused control implements the text UIA pattern, UIA is already loaded, and if the OS is >= RS1.
This means that even if the exposed TextPattern is marked read-only, WPF will request the KB to show.
What is actually needed is a finer grained set of conditions.
- Don't call TryShow if the
TextPatternimplementation declares it is read-only - Don't call TryShow if the focus tracking for the touch KB does not use UIA, but uses TSF (RS3+, but this needs confirmation).
This can be mitigated in later OSes (RS3+) by setting the AppContext flag DisableImplicitTouchKeyboardInvocation. This stops WPF from calling InputPane.TryShow but the KB focus tracking and invocation will still work.