>>Something like:
>>

>><ScrollViewer HorizontalScrollBarVisibilitty="Auto" VerticalScrollBarVisibility="Auto">
>>    <TabControl>
>>        <TabItem>
>>            <Grid>
>>                <Grid.ColumnDefinitions>
>>                    <ColumnDefinition Width="300"/>
>>                    <ColumnDefinition/>
>>                </Grid.ColumnDefinitions>
>>                <StackPanel>
>>                        <!-- Main Content, allow horizontal scrolling, don´t allow vertical scrolling-->
>>                </Stackpanel>
>>                <StackPanel Grid.Column="1">  // Allow Vertical Scrolling
>>                     <Expander>
>>                            <!-- Description 1 -->
>>                     </Expander>                     
>>                     <Expander>
>>                            <!-- Description 2 -->
>>                     </Expander>                     
>>                     <Expander>
>>                            <!-- Description 3 -->
>>                     </Expander>                     
>>                </StackPanel>
>>            </Grid>
>>        </TabItem>
>>        ...
>>    </TabControl>
>></ScrollViewer>
>>

>
>Why can't you use two ScrollViewers' (one for each column) as I suggested ?


You could also use a grid splitter and in the mouse event, disallow any movement to the left.. that's what we do in our program..