FWIW, When we designed the tab order logic for web 2, we were trying to balance what a desktop user would expect with what was possible on the supported browsers. There were some rules we tried to keep in mind:
- focusable controls must be visible and enabled to accept focus
- Tabbing should select the next control within the current WebView.
- if the next “control” in the tab order is a subclass of WebView, control is transferred to that view and its first control receives focus.
- if there is no “next” control in the view and the view is not a WebPage or a WebDialog, control is transferred to the view’s parent view and its “next” control gets focus.
- if there is no “next” control and the view is a WebPage or a WebDialog, focus loops around to the first control on that view.
- each view keeps track of the index of its currently focused control so that parenting thing will work.
Keep in mind that this should also work in reverse if the user is pressing SHIFT-TAB.
Accessibility
Lastly, an option was added just before I left Xojo to allow users to turn off the Xojo tab order engine for users who use screen readers or other accessibility tools. The only ones I see in autocomplete are Session.AllowTabOrderWrap and WebView.AllowTabOrderWrap which according to the docs is what they were renamed to although the name doesn’t fully represent what’s actually going on.
It should be set to False for webpages that will be used by users who depend on accessibility settings that allow them to tab to the browser’s toolbar controls.
Contrary to the documentation, my recollection is that this property is not completely “design-time only” and just needs to be set before the Opening event finishes on either WebSession or WebPage. @Ricardo_Cruz could clarify that for us.
In any case, it’s really important that you set the tab order if you’re using Xojo’s engine (the default).
TL;DR
In the end, I tried creating a WebDialog to test a theory and found that (at least on Mac) if you don’t have Full Keyboard Access turned on in your system preferences, buttons on the web layout do still get focus but they no longer change color. IIRC, they used to get slightly darker when they got focus, but I could be mis-remembering.
Edit: Apparently the focus color does work if there’s more than one button on the dialog.