Public bug reported:

This is similar in some ways to
https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1181666 but
affects only the mouse, not the keyboard, and is consistent almost all
(99%+) of the time.  This is happening for Ubuntu 18.04.2 LTS (bionic)
in the default desktop environment (Ubuntu).  It also happens for the
GNOME and GNOME Classic desktop environments.  The version of gnome-
shell is 3.28.3-0ubuntu0.18.04.4.

Our program is a blend of C# winforms (Mono) with embedded web browser
windows using Geckofx45 (mozilla version 45).  Editing windows in the
program use HTML to display formatting and  typescript/javascript code
to assist with popup dialogs and other editing help.  Inside these
editing windows, left mouse clicks are essentially ignored.  Keyboarding
still works fine as far as I can tell.  Clicking on the gear button
inside the editing window fails to bring up the Styles dialog more than
95% of the time.  When the dialog does display, it is always (100%)
nonfunctional as the first click in it causes it to close immediately.

Tracing the internal behavior of the code, it appears that clicking the
first time inside the editing (browser) window causes a series of
WM_FOCUS messages to be sent and the javascript to hook up a left mouse
click handler to a gear button displayed in the lower left corner of the
editing window.  This is the expected behavior, and the same as on other
window managers.  But then, on GNOME Shell only, a series of
WM_KILLFOCUS messages are sent immediately.  This does not happen for
other window managers.  (The main window receives a WM_ACTIVATE message
with the argument to make it deactivate.)  Any other left mouse clicks
inside that window are ignored >95% of the time, probably only when
double clicking quickly enough to occur before those messages to lose
focus/deactivate are handled.  (Right mouse clicks are handled at a
higher level and appear to function normally.)

The program in question is called Bloom.  The source code is available
at https://github.com/BloomBooks/BloomDesktop and prebuilt debian/ubuntu
packages are available at http://packages.sil.org/ubuntu/ as bloom-
desktop or bloom-desktop-beta.  After spending a few days looking at
this problem, I've reluctantly come to the conclusion that it must be a
GNOME Shell bug that I can't work around in our code.  It's working fine
in Microsoft Windows and all the other Linux window managers that I've
tested (Unity, Cinnamon, KDE Plasma, MATE, XFCE, and LXDE).

** Affects: gnome-shell (Ubuntu)
     Importance: Undecided
         Status: New

** Attachment added: "picture showing Editing window in Bloom.  Mouse clicks 
work fine in the picture box at the top, just not in the text box at the 
bottom."
   
https://bugs.launchpad.net/bugs/1816634/+attachment/5239915/+files/BloomEditingWindow.png

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https://bugs.launchpad.net/bugs/1816634

Title:
  GNOME Shell consistently ignores mouse clicks in a particular app
  window

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