Bitmap %s not found
The control references a bitmap resource that does not exist in the project. As a result, the control will not display anything.
If you want the control to display a bitmap resource, you should select an existing bitmap resource. On the other hand, if the control should display something else (like text or an icon), you should select the appropriate content type in the control's attributes pane.
This message can also appear if the control is localized and you did select an existing bitmap resource for some languages, but not for the current target language (as shown in the Language column of the Diagnostics pane). In that case, either disable localization for the control, or select an existing bitmap resource for this language.