Commented Unassigned: Transparent Background in RichTextBox [20547]

When setting Colors.Transparent as FontBackgroundColor the Background changes to Colors.White.
So instead of setting Color.Transparent in ApplyPropertyValueToSelectedText the background should be cleared.

My current workaround in RichTextBoxFormatBar looks like this

```
void ApplyPropertyValueToSelectedText(DependencyProperty formattingProperty, object value)
{
if ((value == null) || (Target == null) || (Target.Selection == null))
return;
if (value is SolidColorBrush && (value as SolidColorBrush).Color == Colors.Transparent)
{
Target.Selection.ApplyPropertyValue(formattingProperty, null);
}
else
{
Target.Selection.ApplyPropertyValue(formattingProperty, value);
}
}
```
Comments: ** Comment from web user: BoucherS **

Hi,

How do you reproduce the issue ? I try a RichTextBox, with a green background. When I select the text with the mouse I change what the Tooltip calls "Text HighLight Color" to Transparent. Result : the font has a transparent background (green color is seen) as expected.