The following parts of the SysTabControl32 API (Windows 10) are not used:

Control styles:
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- TCS_FOCUSNEVER (https://msdn.microsoft.com/en-us/library/ms650931.aspx)
	-> would require different OLEMISC_* flags and therefore can't be implemented without creating an additional control

Messages:
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- TCM_REMOVEIMAGE (https://msdn.microsoft.com/en-us/library/ms651064.aspx)
	-> questionable benefits
	-> can be used easily via SendMessage()
- TCM_SETITEMEXTRA (https://msdn.microsoft.com/en-us/library/ms651070.aspx)
	-> too difficult to handle, because we would need a way to make the ITabStripTab::TabData property accept data of the correct size only
	-> probably noone really needs this feature

Notifications:
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- TCN_KEYDOWN (https://msdn.microsoft.com/en-us/library/ms650956.aspx)
	-> doesn't seem to have any benefit over WM_KEYDOWN

Flags:
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- TCITEM/TCIF_RTLREADING (https://msdn.microsoft.com/en-us/library/ms650940.aspx)
	-> can't be used because there's no way to retrieve whether a tab has this flag set

Other:
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- Support for multiple (drop-)highlighted tabs
	-> SysTabControl32 can have more than one highlighted tab at once