PR# 19869 Autocompletion window flashes and disappears

When I type the name of a variable followed by ".", the documentation tells me an autocompletion window should pop up with a list of the features available on the object in question.  This works as described in the Mac installation of Eiffel Studio 22.05, but in the Linux version what happens is that a small window flashes on the screen and disappears.  In some cases, I can see that it looks like the autocompletion windows I see in the product screenshots (or on the Mac), and in other cases the only trace of an attempt to pop up a window is the brief appearance of a rectangle on the screen, which then disappears.

The popup window is not, as far as I can tell, being occluded behind some other window; moving windows around on the screen or using alt-` to move among the windows of a given application do not reveal an autocompletion window in hiding.  They seem to show on the contrary that the autocompletion window has been dismissed.

This is a shame because I can tell from my brief experiment on the Mac this afternoon that working autocompletion windows would be a real convenience.

In case it matters, my package manager says my system is using glibc 2.34-0ubuntu3.2 and libgtk-3-0 version 3.24.30-1ubuntu1.

Open a project.  Edit the source code.  In any feature call, delete the name of the feature and the dot separating the variable from the feature name.  Type the dot again.  There will be a brief flash as a window is drawn and immediately deleted.

For what it's worth, I can report a bit of additional information.

First, if I make a new user account on my Pop!OS machine, the autocompletion window appears as expected in Eiffel Studio.  From this, I infer that the problem is not in the machine or in the operating system or in the packages that have been installed, but somewhere in the dynamic environment of a particular user.  I have not found anything promising in the environment variables or in the Pop!OS Settings interface but I'll keep looking as long as I can think of places to look.  Getting Eiffel Studio running for another user account on this machine did help me find the cause of my other problem report (https://support.eiffel.com/report_detail/19868) and I am hopeful that it can help with this one as well.

Second, in an attempt to see if I could provoke Eiffel Studio into giving more information about the problem with the popup autocompletion windows, I invoked ec with the options "-debug -gui -stop". Then in Eiffel Studio I opened a proje
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Thanks for your response.

I'm running Pop!OS on a System76 Galago Pro; the Settings / About interface entry for Graphics reads "Mesa Intel UHD Graphics (CML GT2)".  No virtual machine. 

It began as a default installation in the sense that I didn't do anything unsual, but I have indeed installed a number of applications and packages since then.

Before installing Eiffel Studio I used the Synaptic package manager to install or upgrade the packages listed in the installation instructions for Linux  at https://www.eiffel.org/doc/eiffelstudio/Linux -- I think glibc may already have been above 2.7, but I do remember installing or upgrading GTK 3.

As regards xorg and wayland, Synaptic tells me that both are currently installed and both are marked as supported.  It appears that X11 is in use, not wayland -- at least, "echo $XDG_SESSION_TYPE" returns "x11" and the various other tests one finds on the web for determining whether X11 or Wayland is being used all seem to say X11.  

Since you say the problem
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We tried on default installation of Pop!os 22.04 and we don't see such issue with auto completion popup dialog.
In our case, Pop!OS is running inside a QEMU/KVM machine, and we installed the default one  (not the NVIDIA version).

We haven't tried on Pop!OS  21.10, and neither with NVIDIA version.

The install libgtk-3 is version 3.24.33, so I don't think this would explain the difference.

Can you tell us a bit more about your environment?
- NVIDIA?
- inside a virtual machine, or no
- is it default installation, or you did installed extra package, eventually manually upgraded a few packages like libgtk-3 ? 
- I guess Pop!OS uses xorg, and not wayland as default, but do you confirm you are not using wayland?

On Linux, it happens sometime that user may have UI issue when it is not the standard installation ... and this is the main issue with Linux, there are so many different flavor and customization, this is sometime hard to support all cases. That's also the beauty of Linux to have such diversi
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