Something I would've expected to have no issues, but a simple toolbar/toolbar button in Mozilla has the image stretched to display across the entire button. Debatably worse, the button is non-functional/NavigateUrl does not work (and, no, there are no Javascript errors on the page).
Works fine in IE.
The image in question is 44x39, so size shouldn't be an issue.
An example with Mozilla on the top, IE on the bottom can be found here:
RadToolBarButton issue
http://siffalo.com/toolbar.jpg
And here's the mark-up with ToolTip and NavigateUrl removed for brevity:
<telerik:RadToolBar runat="server"><Items><telerik:RadToolBarButton ToolTip="..." NavigateUrl="..." ImageUrl="~/images/xDIcon44Shadow.png" Text="Your xDComposer Solution" CssClass="utWizardButton"></telerik:RadToolBarButton></Items></telerik:RadToolBar>
utWizardButton is just:
{ width: 192px }
Removing that just makes the buttons variable width.
The example above is in a RadGrid template column, but the issue also happens in the content of a RadDock, so I don't think it's particularly related to a specific parent control.