I am using the xamRibbon and within one of the RibbonGroups I have a GalleryTool and a ToolVerticalWrapPanel. After upgrading to 10.3 we got the use of the text labels on the gallery items working but there is a weird case where, given certain widths, if you extend the window so that the gallery is only one row then the gallery can start cutting off the ToolVerticalWrapPanel until it is very thin or not visible. Here is the xaml and a screen shot. There also cases where the tools are completely gone. I have tried setting minWidths on the ButtonTools and the ToolVerticalWrapPanel but have not found one that will stop this behavior.

   <igRibbon:RibbonGroup Name="ThemeGallery" Caption="Theme Gallery" MaxWidth="500" SmallImage="..\Images\Ribbon\ColorSwatch16.png">
        <igRibbon:RibbonGroup.Variants>
            <igRibbon:GroupVariant Priority="4" ResizeAction="ReduceGalleryPreviewItems"/>
            <igRibbon:GroupVariant Priority="5" ResizeAction="CollapseRibbonGroup"/>
        </igRibbon:RibbonGroup.Variants>
         
        <igRibbon:MenuTool
                                    ShouldDisplayGalleryPreview="True"
                                    LargeImage="..\Images\Ribbon\ColorSwatch32.png"
                                    SmallImage="..\Images\Ribbon\ColorSwatch16.png" >
            <igRibbon:GalleryTool Name="ThemeGalleryTool" Id="themeGallery" ItemBehavior="Button">
 
            </igRibbon:GalleryTool>
        </igRibbon:MenuTool>
        <igRibbon:ToolVerticalWrapPanel>
            <igRibbon:ToggleButtonTool 
                                    Name="tbContinuousTheme" 
                                    Id="" SmallImage="..\Images\Ribbon\Continuous16.png"
                                    igRibbon:RibbonGroup.MaximumSize="ImageOnly"
                                    ToolTip="Continuous Mode" 
                                    KeyTip="MT"
                                    IsEnabled="False"
                                    IsChecked="{Binding Path=IsOnDemandQueryMode, Mode=TwoWay}"/>
            <igRibbon:ButtonTool 
                                            Name="btnNewUserTheme" 
                                            Id="" 
                                            igRibbon:RibbonGroup.MaximumSize="ImageOnly"
                                            SmallImage="..\Images\Ribbon\New16.png" 
                                            IsEnabled="True"
                                            ToolTip="Create New Theme"                
                                            Click="showThemeBuilder" />
            <igRibbon:ButtonTool                                                                                       
                                            SmallImage="..\Images\Ribbon\Load16.png" 
                                            igRibbon:RibbonGroup.MaximumSize="ImageOnly"
                                            IsEnabled="True"
                                            ToolTip="Load Theme"
                                            Click="LoadThemeFromFile"/>
        </igRibbon:ToolVerticalWrapPanel>
    </igRibbon:RibbonGroup>