fix: ButtonBase should not lose focus when Command.CanExecuteChanged …

…becomes false

src/Uno.UI/UI/Xaml/Controls/Control/Control.cs

@@ -795,8 +795,11 @@ private protected override void OnIsEnabledChanged(IsEnabledChangedEventArgs e)
 				}
 			}
 
+			// TODO Uno specific: Adding check for IsEnabledSuppressed here
+			// as we need to make sure that when a Command is executing, the control
+			// should not lose focus
 			bool shouldReevaluateFocus =
-				!IsEnabled && //!pControl->ParserOwnsParent()
+				!(IsEnabled || IsEnabledSuppressed) && //!pControl->ParserOwnsParent()
 				!AllowFocusWhenDisabled &&
 				// We just disabled this control, find if this control
 				//or one of its children had focus.

src/Uno.UI/UI/Xaml/FrameworkElement.cs

@@ -720,14 +720,19 @@ private protected virtual void OnIsEnabledChanged(IsEnabledChangedEventArgs pArg
 		}
 		#endregion
 
+		internal bool IsEnabledSuppressed => _suppressIsEnabled;
+
 		/// <summary>
 		/// Provides the ability to disable <see cref="IsEnabled"/> value changes, e.g. in the context of ICommand CanExecute.
 		/// </summary>
 		/// <param name="suppress">If true, <see cref="IsEnabled"/> will always be false</param>
 		private protected void SuppressIsEnabled(bool suppress)
 		{
-			_suppressIsEnabled = suppress;
-			this.CoerceValue(IsEnabledProperty);
+			if (_suppressIsEnabled != suppress)
+			{
+				_suppressIsEnabled = suppress;
+				this.CoerceValue(IsEnabledProperty);
+			}
 		}
 
 		private object CoerceIsEnabled(object baseValue)