I realized that the SuffixContentControl's DesizredSize.WIdth is 0 when PART_HeaderItemsControl's width is large enough. so SuffixContentControl is hidden.
After I add MinWidth for the column show SuffixContentControl like below, the SuffixContentControl is visiable again.
As you can see, I alter the TabablzControl class, add a DependencyProperty HeaderSuffixContentMinimumSize in it. And you can use TabablzControl in your code like below:
I check the Generic.xaml, ans saw below code of TabablzControl style.
I realized that the SuffixContentControl's DesizredSize.WIdth is 0 when PART_HeaderItemsControl's width is large enough. so SuffixContentControl is hidden.
After I add MinWidth for the column show SuffixContentControl like below, the SuffixContentControl is visiable again.
As you can see, I alter the TabablzControl class, add a DependencyProperty
HeaderSuffixContentMinimumSize
in it. And you can use TabablzControl in your code like below: