[SmartHint] Fix minor UI jump (#3768)

* Add TextBox.IsReadOnly option to "fields line up" demo pages

* Add extra condition in converter to avoid minor UI jump

Author: nicolaihenriksen

src/MainDemo.Wpf/FieldsLineUp.xaml

@@ -108,6 +108,7 @@
             <CheckBox x:Name="IsEnabledCheckBox"
                       Content="IsEnabled"
                       IsChecked="True" />
+            <CheckBox x:Name="IsReadOnlyCheckBox" Content="TextBox.IsReadOnly" />
             <CheckBox x:Name="HasClearButtonCheckBox" Content="TextFieldAssist.HasClearButton" />
             <CheckBox x:Name="IsEditableCheckBox" Content="ComboBox.IsEditable" />
           </StackPanel>

src/MainDemo.Wpf/FieldsLineUp.xaml.cs

@@ -52,6 +52,8 @@ public FieldsLineUp()
             control.Margin = new Thickness(2, 10, 2, 10);
             if (control is ComboBox comboBox)
                 comboBox.SetBinding(ComboBox.IsEditableProperty, new Binding(nameof(CheckBox.IsChecked)) { ElementName = nameof(IsEditableCheckBox) });
+            if (control is TextBoxBase tb)
+                tb.SetBinding(TextBoxBase.IsReadOnlyProperty, new Binding(nameof(CheckBox.IsChecked)) { ElementName = nameof(IsReadOnlyCheckBox) });
             SetValue(control);
         }
     }

src/MaterialDesign3.Demo.Wpf/FieldsLineUp.xaml

@@ -97,6 +97,7 @@
           <CheckBox x:Name="IsEnabledCheckBox"
                     Content="IsEnabled"
                     IsChecked="True" />
+          <CheckBox x:Name="IsReadOnlyCheckBox" Content="TextBox.IsReadOnly" />
           <CheckBox x:Name="HasClearButtonCheckBox" Content="TextFieldAssist.HasClearButton" />
           <CheckBox x:Name="IsEditableCheckBox" Content="ComboBox.IsEditable" />
         </StackPanel>

src/MaterialDesign3.Demo.Wpf/FieldsLineUp.xaml.cs

@@ -52,6 +52,8 @@ public FieldsLineUp()
             control.Margin = new Thickness(2, 10, 2, 10);
             if (control is ComboBox comboBox)
                 comboBox.SetBinding(ComboBox.IsEditableProperty, new Binding(nameof(CheckBox.IsChecked)) { ElementName = nameof(IsEditableCheckBox) });
+            if (control is TextBoxBase tb)
+                tb.SetBinding(TextBoxBase.IsReadOnlyProperty, new Binding(nameof(CheckBox.IsChecked)) { ElementName = nameof(IsReadOnlyCheckBox) });
             SetValue(control);
         }
     }

src/MaterialDesignThemes.Wpf/Converters/FloatingHintInitialHorizontalOffsetConverter.cs

@@ -41,7 +41,7 @@ double GetLeftOffset()
                     when prefixHintBehavior == PrefixSuffixHintBehavior.AlignWithText && isEditable =>
                     prefixWidth + prefixMargin.Right,
                 PrefixSuffixVisibility.WhenFocusedOrNonEmpty
-                    when prefixHintBehavior == PrefixSuffixHintBehavior.AlignWithPrefixSuffix && !isEditable =>
+                    when prefixHintBehavior == PrefixSuffixHintBehavior.AlignWithPrefixSuffix && !isEditable && prefixWidth > 0 =>
                     -(prefixWidth + prefixMargin.Right),
                 PrefixSuffixVisibility.Always
                     when prefixHintBehavior == PrefixSuffixHintBehavior.AlignWithPrefixSuffix =>
@@ -58,7 +58,7 @@ double GetRightOffset()
                     when suffixHintBehavior == PrefixSuffixHintBehavior.AlignWithText && isEditable =>
                     -(suffixWidth + suffixMargin.Left),
                 PrefixSuffixVisibility.WhenFocusedOrNonEmpty
-                    when suffixHintBehavior == PrefixSuffixHintBehavior.AlignWithPrefixSuffix && !isEditable =>
+                    when suffixHintBehavior == PrefixSuffixHintBehavior.AlignWithPrefixSuffix && !isEditable && suffixWidth > 0 =>
                     suffixWidth + suffixMargin.Left,
                 PrefixSuffixVisibility.Always
                     when suffixHintBehavior == PrefixSuffixHintBehavior.AlignWithPrefixSuffix =>