Windows 95 and a Bizarre Case of Font Drag and Drop

Alberto Marnetto's Notebook

Windows 95 and a Bizarre Case of Font Drag and Drop

or: A Supposedly Fun Thing I'll Never Do Again

About twenty-seven years ago I discovered a quirk in Windows 95 (and 98). To my knowledge, it has never been published. Well, it’s never too late.

The benign variant

1. Open two Explorer windows. One of those must be in the Fonts directory.

2. Select all fonts, then deselect the one you want to use for the effect.

3. Drag the selection to the other window and, surprise, all the labels you touch are changing typeface! Take care to not drop the fonts, otherwise they will be moved, which will lead to many other problems. Keep hold of them and drag them back, or use the right mouse button to do the dragging, so that you can cancel the operation if you accidentally drop them.

4. After a refresh (F5), all labels are using the new font.

Unfortunately, the effect does not persist after you close the window. You can however apply the trick to the taskbar, whose buttons will then use the new font for the rest of the session. As expected, the System properites dialog does not acknowledge the change and can be used to restore the original font.

The nasty variant

What if you do not deselect any font and drag all files? Things get slightly worse:

1. When you drag the fonts, the labels receive what appears to be Windows 3.1's sans serif font.

2. The effect expands to all open windows after refresh, and even the title font is changed to a typeface I cannot recognize.

3. The title font change is permanent during the session.

Some considerations

To showcase the phenomenon I have used the online VMs by PCjs Explorer, but I vividly remember discovering it on my old Pentium 75, so it’s not an emulator bug. I was able to reproduce the glitch also in copy’s website, though the effect is less spectacular because the Internet Explorer addition running on his VM prevents the menu font to be altered. However, the fact that it works further proves that it’s not a fluke. The trick also works in Windows 98. I have not tried further versions, but feel free to experiment and send me your results.

Now, why does this happen? If I had infinite time, I’d love to start a debugger and find out what messages are being sent to the windows, but even a technical explanation would still not solve the mystery of why this behavior was implemented in the first place. Since nobody is here to tell the story, here is my headcanon:

OS/2 supports changing font via drag and drop: see this guide.
Someone at Microsoft got tasked with reproducing this functionality in Win95.
The feature got implemented, but it was found to be too brittle, or maybe confusing for users who just wanted to copy the font file to another folder and not change the typeface.
The code section activating the font change when a “font file dropped” message was disabled, but they forgot to deactivate the trigger for the event “multiple font files dropped”.

But this is just my theory. In particular, the strange effect shown by the nasty variant suggests that some out-of-bounds access is taking place.

I guess the real story will remain a mystery forever. Unless some Microsoft veteran lands by chance on these shores and wants to share the tale. Raymond Chen, are you by any chance reading? Please, don’t keep us in the dark!

Update

Reddit user “fragglet” suggested that the effect can be explained if we suppose that the files being dragged are already considered “missing” from the source directory, so that Windows is forced to use the only remaining font (in the first variant) or an emergency typeface (in the second case). This seems to agree with most of the observations of the experiment. If the explanation is correct it means that Windows is mixing UI and underlying file system in a very questionable way.

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