I strongly disagree with the Tim Dawsons's view.
Introduction:
Currently text box user settings are not respected. For instance I personally prefer the TextBox with violet background and white text
because with standard white background my eyes start to hurt after several hours. But when I tried to set the Window color on my computer
to violet and the foreground to white I noticed that many applications including Microsoft Access (2003) could not handle this. I often
encountered white text on white backgound. So I had to switch back to the standard white background and black text. This clearly shows that
user settings are not respected. With application themes it would be possible to assure that at least for the application I'm writing that
the user can choose the settings he really likes.
I did some research on this and found out that many people actually don't like the white background if they have to sit a long time before
the computer. But most users don't even know that the color settings of the Window defined in the Advanced Appearance dialog box refers to
the color of a text box. But even if they know they cannot change it because many applications use only the WndForeground color and then
display white text on white background. So nobody can claim that user settings are currently respected. The default is white not because
most users like it but because the paper is white and in the past application had difficulty with printing if the background color of the
screen was different to the paper color. But nowadays this problem is gone and there is no need to always use white background in WPF.
WPF text box selection color missing:
The lack to define a selection color is the single biggest shortcoming in WPF. To illustrate this it is necessary to define a view
abbreviations:
UserDefSelCol = The 'selected items' color the user has defined in the Advanced Appearance dialog box
WndForeground = The 'Window' font color the user has defined in the Advanced Appearance dialog box
WndBackground = The 'Window' color the user has defined in the Advanced Appearance dialog box
First take note that there is no specific color defined in Advanced Appearance dialog box for a text box so it is not possible to
disrespect the users settings for text boxes. The WndForeground and WndBackground colors are only used because these are the closest
available user defined colors. An application may accommodate much more specific user options to present the application in such color
settings as really preferred by the user.
There is only one WndBackground and one WndForeground color defined. If it would be always required to respect the user settings then what
is the need of Foreground and Background properties in WPF. This would surely diminish the richness of WPF. This would mean an application
cannot let the user choose from a number of application themes because if the theme alters the background color of TextBox the selection
may no longer be clearly visible.
Currently with .Net 3.5 and .Net 4 beta it is not possible to create application themes in a satisfactory way. By application theme I mean
a xaml resource that overrides the styles for all controls used in the application including TextBox/TextBoxBase. If the UserDefSelCol is
violet and I set in my application theme the TextBox background to violet the selection will no longer be visible. Even if the selection
color and the background colors are not the same, often the selection is hard to see because the selection color is too close to the
background color. Once the background color is changed the selection color needs to be adjusted to provide sufficient contrast to see the
selection clearly. But unfortunately there is currently no way to set the selection color of a TextBox object.
There are two possibilities to solve this problem in WPF:
A: Implement an algorithm that always automatically creates a clearly visible selection color depending on the actual background color of
the text box at the time of selection.
B. Implement a TextBoxBase.SelectionColor property
Selection Color of a TextBox
If I were to make a list of native controls I'd *least* want to reinvent, TextBox would be toward the top of the list (and anything else dealing with text input would be very close behind).