Microsoft has deprecated MDI for new applications long, long ago (maybe even in Windows 98 times)
Correct. Actually Windows 95!
https://docs.microsoft.com/en-us/cpp/mfc/sdi-and-mdiMore than 20 years ago in favor of SDI (single document interface).
The tabbed document interface was introduced to mitigate some usability problems with SDI (which docs are opened?) and is from a later date.
MS sinned against their own advice, though, e.g. excel up to but not including 2007.
From Joel Spolski (in 2002):
"Here are the usability problems people have with MDI:
* They accidentally minimize a child window, e.g. by double clicking it's title bar, and don't know what they've done. Then they think the other windows are lost.
* They get into a state where the child windows are not even visible because the main window is too small or scrolled away, and don't know what they've done. Then they think the window is lost, and choosing it from the Window list does nothing.
* They close the app when they meant to close a child window because the X's icons are so close.
There are a whole range of other pathologies. Programmers are very logical people and understand MDI quickly. Most end users just don't get it and usability on these apps is terrible.
Joel Spolsky " http://discuss.fogcreek.com/joelonsoftware/default.asp?cmd=show&ixpost=2748I can confirm the last line:
Together with my then emplorer we did some usability tests in a software testlab in Delft (WITlab TU Delft 1997-1998) for our nextgen product. Usability experience by end users with MDI was horrible. Our then core product was MDI......
I subsequently designed a TDI/SDI based interface, but around that time/soon after I left the company.
It was also the only time in my carreer we overshot the development budget by - a lot - more than multiplied with Pi. Excellent technology previews and proof of concept, though..
WITlab means "Work and Integration Laboratory". It is still a world leader in usability.