Accessibility (Screen Readers)
SftTabs/DLL 7.0 ships with built-in Windows UI Automation (UIA) support. Users who rely on Narrator, NVDA, JAWS or any other UIA-compatible assistive technology can read and navigate SftTabs controls without the hosting application doing any work. No opt-in, no code change, no separate build.
What the screen reader sees:
| Control type | Tab. The root advertises UIA_TabControlTypeId with IsSelectionRequired=TRUE and the Selection pattern. Automation harnesses and AT software can enumerate the tabs, query the , and switch tabs programmatically. |
| Tab items | One TabItem child per real tab (visible and hidden). Each tab item advertises the SelectionItem pattern - activation is via SelectionItem.Select per the UIA spec (TabItems do not advertise Invoke). Hidden tabs still appear in the tree with IsOffscreen=TRUE so AT clients can discover them. |
| Tab item properties | Name from the tab label with & mnemonic markers stripped (spec requirement); AccessKey carrying the mnemonic character; HelpText from the tab's lpszToolTip so the same text shown as an on-hover tooltip is also announced; IsEnabled from fEnabled && !fHidden; PositionInSet / SizeOfSet for set context; HasKeyboardFocus set on the when the control has focus. |
| Chrome buttons | Button elements for the scroll-left, scroll-right, close, minimize, and restore chrome buttons (when they exist as HWNDs). Each advertises Invoke. Name is a short identifier ("Close", "Minimize", "Restore", "Scroll Left", "Scroll Right"); HelpText carries the per-button tooltip set on the control (szCloseToolTip / szMinimizeToolTip / etc.). |
| Per- | When a tab's fHasCloseButton is TRUE, the tab exposes a nested Button child with the Invoke pattern. Invoking the synthesizes a click on the tab's second-picture area - the same code path as a real click, so the application receives the standard SFTTABSN_LBUTTONDOWN_IMAGE2 notification. Tabs without fHasCloseButton remain childless. |
Automatic event notifications raised to UIA clients: Selection_Invalidated + AutomationFocusChanged on every tab switch, StructureChanged on tab insert / delete / reset / move / layout, AutomationFocusChanged on focus changes. All events are internally guarded by UiaClientsAreListening so the cost when no assistive technology is attached is one cached function-pointer call.
There is nothing to turn on. The provider loads on demand the first time a UIA client queries the control, so there is no overhead for applications whose users never attach an assistive technology.
Two things the application controls:
- Set per-tab tooltip text (lpszToolTip in SFTTABS_TAB) so the on-hover tooltip text is also announced to screen readers as the tab's HelpText. Set per-button tooltip text (szCloseToolTip, szMinimizeToolTip, szRestoreToolTip, szLeftToolTip, szRightToolTip on SFTTABS_CONTROL) for the chrome buttons.
- Call Announce to push short application-status text ("Saved", "Tab closed", "Switched to page 3 of 5") to attached screen readers. Announce is the right tool for momentary status updates that do not have a visible representation in the tab control.
Dark mode and Windows High Contrast are independent accessibility settings. SftTabs honors both automatically (see SetDarkMode and SetHighContrastMode).
Platform note: The UIA notification event used by Announce requires Windows 10 version 1709 or later. On earlier platforms Announce is a silent no-op. All other UIA features work on Windows 7 and later.
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