After searching through all the posts that said this was not possible, I decided to ignore all of them and make it possible. Today, I finally figured it out.
Code:
<TabBox item ="IW_SubTabs">
<ScreenID>SubTabs</ScreenID>
<RelativePosition>true</RelativePosition>
<AutoStretch>true</AutoStretch>
<TopAnchorToTop>true</TopAnchorToTop>
<BottomAnchorToTop>false</BottomAnchorToTop>
<LeftAnchorToLeft>true</LeftAnchorToLeft>
<RightAnchorToLeft>false</RightAnchorToLeft>
<TabBorderTemplate>FT_DefTabBorder</TabBorderTemplate>
<PageBorderTemplate>FT_DefPageBorder</PageBorderTemplate>
<Pages>Page:IW_SubTabStuff</Pages>
<Pages>Page:IW_MoreSubTabStuff</Pages>
</TabBox>
<Page item="IW_TabbedPage">
<ScreenID>StatPage</ScreenID>
<RelativePosition>true</RelativePosition>
<DrawTemplate>WDT_Def</DrawTemplate>
<TabText>Stats</TabText>
<TabTextColor>
<R>0</R>
<G>240</G>
<B>0</B>
</TabTextColor>
<TabTextActiveColor>
<R>255</R>
<G>255</G>
<B>0</B>
</TabTextActiveColor>
<Style_Sizable>true</Style_Sizable>
<Pieces>TabBox:IW_SubTabs</Pieces>
</Page>
Of special note, is the TabBox portion under Pieces. This is what was stumping me. It is not used in the normal tab box before making your final page.
Code:
<TabBox item ="IW_Subwindows">
<ScreenID>IW_Subwindows</ScreenID>
<RelativePosition>true</RelativePosition>
<AutoStretch>true</AutoStretch>
<TopAnchorToTop>true</TopAnchorToTop>
<BottomAnchorToTop>false</BottomAnchorToTop>
<LeftAnchorToLeft>true</LeftAnchorToLeft>
<RightAnchorToLeft>false</RightAnchorToLeft>
<TabBorderTemplate>FT_DefTabBorder</TabBorderTemplate>
<PageBorderTemplate>FT_DefPageBorder</PageBorderTemplate>
<Pages>Page:IW_TabbedPage</Pages>
<Pages>Page:IW_SomeOtherTabbedPage</Pages>
</TabBox>
<Screen item="NestedTabWindow">
<RelativePosition>false</RelativePosition>
<Location>
<X>100</X>
<Y>50</Y>
</Location>
<Size>
<CX>266</CX>
<CY>446</CY>
</Size>
<Text>Inventory</Text>
<Style_VScroll>false</Style_VScroll>
<Style_HScroll>false</Style_HScroll>
<Style_Transparent>false</Style_Transparent>
<TooltipReference>Inventory</TooltipReference>
<DrawTemplate>WDT_RoundedNoTitle</DrawTemplate>
<Style_Titlebar>false</Style_Titlebar>
<Style_Closebox>false</Style_Closebox>
<Style_Minimizebox>false</Style_Minimizebox>
<Style_Border>true</Style_Border>
<Style_Sizable>false</Style_Sizable>
<Pieces>IW_Subwindows</Pieces>
</Screen>
Notice no tab box mention in the final window for Tabs.
So, there you have it. A nested tab window. My inventory window will be using this feature and will be uploaded as soon as I finish fine tuning it. Please feel free to ask any questions about this or anything else I may have worked on. Enjoy!