Opening a PDF File Causes Windows 10 "Show shadows under windows" to Deselect

I have this too with acrobat dc pro, whenever I press comment, shadows under windows disappear. So once we don't have any update by adobe, I made a workaround so I don't need to turn on shadows every single time I open pdf's. I turn on the little border in windows (this is turned off, but to turn it on is very easy), i don't have the shadows but with this 1px border, i always see where my windows are and it's easy to resize for example.

It appears you missed a part of the answer, that allows you to set Acrobat so the window shadows do not disappear.

Note, you can turn off a trigger of shadows disappearing under windows by doing the following:

a) With no PDF file open, but application Adobe Acrobat is open

b) Select the "Edit" menu

c) Select Preferences...

d) Under Categories: Select "General"

e) Under Basic Tools check the box for "Open documents as new tabs in the same window (requires relaunch)

f) Be sure to scroll down to select the "OK" button

Grant, this is not a great solution, in fact not really a solution,.I preferr to have documents open in individual windows, and pulling the tabs to make a separate window is an extra step in my production I would prefer not to have to do, but I am dealing with it until Adobe does resolve this isuue.

I am also having this issue and have gone thru the previously documented Acrobat DC uninstall, purge, reinstall process to no avail.  Would love to have a fix for this.

I can confirm this. As described above, to reproduce:

1. [Win]+R > SystemPropertiesPerformance.exe
   (C:\Windows\System32\SystemPropertiesPerformance.exe)
2. Check Show shadows under windows
3. Open Acrobat
4. Clear Edit > Preferences > General > Basic Tools > Open documents as new tabs in the same window
5. Close Acrobat
6. Open any PDF with Acrobat (Running Acrobat itself doesn't trigger the bug)
7. [Win]+R > SystemPropertiesPerformance.exe. Show shadows under windows is cleared and there is no shadow under any window.

This degrade a lot the ergonomics of Windows 10, default theme, as it makes difficut to determine which window will be acted upon with the mouse, which as the keyboard focus, etc.

Reverting the Acrobat setting Open documents as new tabs in the same window to Checked is a workaround.

Thanks a lot to Daniel_M_Schwartz for having sussed and documented all that!

This did not resolve the issue for me. I uninstalled, purged all of the files, restarted and reinstalled and the issue persists. Quite annoying to have Adobe affecting the usability of Windows even outside of Acrobat.