Version: 6.0.0 (but it was also happening in the one before, I just updated to confirm whether it still exists)
Describe the bug
I can trigger this with checking for updates:

Then this in-app notification bubble appears:

And when I AltTab, it appears too

It _seems_ to me this is some buggy thing with PhpStorm in fact.
For example, I trigger the update notification bubble and _don't_ AltTab but hover over it, I see the icons for closing:

Once I AltTab and see this window in use AltTab to chose the notification bubble, those hover icons don't appear anymore:

Sometimes I open phpstorm and open projects, I can't reproduce it immediately. Needed to close it again, open a few (3?) projects, then I could reproduce it 🤷♀️
Hey @mfn! Thanks for sharing this issue!
This is surprising as I use JetBrains products. I'm actually developing AltTab using AppCode. I tried your "Check for updates" reproduction steps, and I can't reproduce. It works correctly:

I'll download PHPStorm and test there
Tested on PHPStorm, and I can't reproduce. I'm on this version:
PhpStorm 2020.2.1
Build #PS-202.6948.87, built on August 27, 2020
Licensed to PhpStorm Evaluator
Expiration date: September 27, 2020
Runtime version: 11.0.8+10-b944.31 x86_64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
macOS 10.15.6
GC: ParNew, ConcurrentMarkSweep
Memory: 725M
Cores: 8
Registry: run.processes.with.pty=TRUE
I use exactly the same version.
Yeah it's also not always reproducible, right now I can't either.
Btw, one awesome thing with the new AltTab version (I think already with 5?) is that, while it is open, I can finally use my screenshot software!
Wasn't possible before, AltTab would always close on me upon triggering the shortcuts I use (ctrl-cmd-a)
Wasn't possible before, AltTab would always close on me upon triggering the shortcuts I use
A trick I use for these kind of scenarios is using the built-in Screenshot.app and put a 5s timer
Nice tip, thanks; will remember it for such cases!
I still prefer to use https://snip.qq.com/ as they provide immediately the ability to draw on the canvas which I do 99% of the time 😆
In the meantime I'm on 6.1.0 and I can't reproduce it either (but it also didn't appear anymore also with the previous version) => closing!
Happened again right now with 6.2.0

Did it happen after your started AltTab? Like PHPStorm was already running and you started AltTab after?
Like PHPStorm was already running and you started AltTab _after_?
No, it was running for a long time already, basically since https://github.com/lwouis/alt-tab-macos/issues/563#issuecomment-688027402
In the meantime I moved to the other version though from https://github.com/lwouis/alt-tab-macos/issues/563#issuecomment-688478090
What about the 2 windows on the left of the notification window? Were they there from the beginning? Did they appear over time, did they appear exactly when the notification window appeared?
How often does this issue happen overall? Like if you close AltTab or PHPStorm now and re-open, is it going to be working fine for a while until it happens again, or is it doing it straight away?
I tried all sorts of things but can't reproduce locally.
Were they there from the beginning? Did they appear over time, did they appear exactly when the notification window appeared?
Yes, they exactly appeared together at the same time!
How often does this issue happen overall? Like if you close AltTab or PHPStorm now and re-open, is it going to be working fine for a while until it happens again, or is it doing it straight away?
It happened this once after a while, because first time after this ticket was closed.
_Maybe_ this is a red herring thing because I temporarily used 5.3.x for the other issue. I.e. maybe I went back to the version which has this problem but maybe 6.x doesn't have it (as I said, haven't seen it since we closed the ticket which AFAIR was before 6.x was out).
I haven't seen it since 6.x but that's not a long time.
I tried some combination with closing AltTab and producing the popup notification in PS and then starting AltTab and the other way around, but not really reproducible.
Maybe I really saw this because I was on 5.x for testing the other issue after all 🤔
Let's keep this ticket open, and please report here if it happens again on the latest versions. Also when it does, please try to remember the chronology of action: when did you start AltTab, when did you start PHPStorm, when did you notice the issue in AltTab.
Also how does it react if you quit PHPStorm, etc
Happened to me again today; very rarely this comes up:

This is with 6.7.4, but after that upgraded to 6.8.0
Seems the DataGrip EAP also has this. I'm not using it as much as PhpStorm, so I didn't notice it until right now:

I do not have that many DataGrip windows open, only two in fact. Stopping/Starting AltTab fixed this, as it was quite persistent and I could not close those "ghost windows" via AltTab (and there existing none otherwise)
This is with the latest AltTab 6.8.0
The small blue rectangles seem to be either text selection or some suggestion? It seems IntelliJ uses window objects for a host of things. It's a cross-platform Java app after all, so it shouldn't be surprising that it doesn't integrate well in macOS. I'm just surprised it never does this behavior on my machine. Maybe you use a certain feature that I don't, or maybe it's a plugin that's causing these.
I keep thinking these days that I should just add size check for the windows, as discussed in #456. It would probably remove all these false-positives at reasonable performance cost.
@mfn here is a local build I made which filters out windows with no size, or a width/height < 100px. Could you try it out and let me know how it works for you? It will be helpful to not only test the Jetbrains EAP apps, but also regular apps to see that there is no regressions. It could filter out actual small windows. I can't imagine a legitimate window that users would want to see in AltTab that would be smaller than this though, but I may be wrong who knows.
@lwouis thank you, I just started it and was pretty quickly able to reproduce it:

Double checked it's not a "released" version:

Now that I think of it, that's definitely a DataGrip EAP thing, I had nothing like that every before. Not in that amount and so easily happening.
How can these windows show when I added the size check? They must be bigger than 100x100 but have transparent regions 🙉
I'll try installing DataGrip to see if I can reproduce. You're making me install the whole Jetbrains suite ;p
You're making me install the whole Jetbrains suite ;p
I am so sorry for that 😱
Well, it's a good suite. The DataGrip EAP is at https://www.jetbrains.com/datagrip/nextversion/
However I do have db connections set up, query them, copy paste columns content (e.g. json), create temporary window to reformat it => so they kind of actions _might_ relate to what kind of "windows" are created…
You mean these are not present after a start? They only appear after you use the app a bunch?
If you could find which steps specifically trigger this, that would be ideal
Omg yes! I could get one glitchy window finally! I set up a connection, and did come copy pastes. I think it's having a tooltip show up on hovering the table that did it though. Update: yes, the tooltip do it for sure, when text doesn't fit in a cell and you hover. I can hover while AltTab is open, and see these pop in and out in AltTab
I'll finally be able to see these windows characteristics!
Oh wow! There was a logic bug in a long boolean expression [1], and after spending 10min looking at it I realized why it was not filtering these windows. I'm surprised not more apps were impacted by the logic bug.
I'm going to push a public release with this change. Could you please tell me if this build fixes it for you? It fixes it for me
[1]

Yes, I think it works now with your latest build. Fooled around in DataGrip but could not reproduce it.
Thanks for the fix! This has been annoying me in the current CLion EAP for a while but I hadn't got around to reporting it.
I am actually still seeing this in CLion EAP a little bit, but it's miles better than it was. I think you've successfully filtered most of the spurious windows that it's creating, but there does seem to be one or two still sneaking past. I'll post again here, or open a fresh issue, if I figure out what they are.
@mparry that's surprising. A screenshot would help here. My assumption was that these windows are small pieces of the UI that Jetbrains coded as dialogs or windows, but that are not that to end user. Probably it's their Java UI (they use Swing I think?) frameworks that maps to macOS AppKit this way.
Based on what thumbnails are shown, i assumed that it would be filtered by not listing windows with no size, or with a size < 100x100.
If you're still seeing glitchy windows it means they are larger than that. It may be a different situation then. It would help if I could see what it looks like. Also as you said, your guess as to how trigger their apparition and what they depict would be most helpful

Do you have consistent steps to reproduce? I need to get it locally to understand why the window is not filtered by it's size since it looks to be 0x0
Sorry, no. Indeed, it hasn't occurred at all today. I did pick up a Rider EAP update this morning, so it's possible they've altered something. Unless anyone else is still seeing anything, I'm personally quite happy for you to leave this issue closed, until more concrete details are available. As I said above, it was rather annoying before because there might be 10+ spurious windows in AltTab, but I haven't seen more than 1 since your last change (and 0 today).
I still don't have a repro but here's a somewhat more informative screenshot:

As you can see, it's a tooltip. However, this certainly doesn't happen every time a tooltip is shown.
Tooltips are not showing for me in CLion (public release, not EAP). That's the IDE I use to develop AltTab, so I think I would have run into the issues by now. This makes me think it's EAP specific, which is also what I observed above with PHPStorm or DataGrip.
It would be nice to get Jetbrains perspective on this issue by reporting it to them. They may shed some light on what they changed in the EAP channel that could create this issue.
I can confirm the bug is still there and relevant for the WebStorm as well. Althought, after the last fix, it become much harder to reproduce - I can work for half a day and not seen any empty items
One way that I can make it happen slightly more reliably - maybe 50% of the time? - is to invoke AltTab while I am actually hovering over code so that a tooltip displays - the tooltip is often then present in the window list. Most of the time, it will disappear if I stop hovering (rather than leaving something permanently in the list, as I see less often) but perhaps this would at least help figure out why it's getting past your filtering.
Yes, I agree with @mparry - it's relatively easy to get the tooltip to alttab with the proposed way (about 20-40% in my case). But tooltips in alttab are not persistent - they will disappear after the tooltip close. But sometimes there can be empty socets that would persist untill IDE restart, like in the initial issue - and that one are much harder to reproduce :( Will keep an eye on what can couse them
relevant for the WebStorm as well
Are you using WebStorm EAP or stable release?
EAP. All this problem started in EAP - the previous stable didn't had this issues
Had this happen today again to me with latest AltTab and EAP:

Just for documentation. But it really happens rarely.
The notification window in question was already long gone at the point I saw it here. Neither focusing not closing it via AltTab was possible.
I even closed all PhpStorm windows so that only the "project chooser" / welcome screen would appear and they would still be displayed via AltTab.
Only when I completely closed PhpStorm, they were gone.
I forgot to test what would have happened if I would have restarted AltTab.
Do you see these windows normally in AltTab? I mean in addition to the fact that they remain after they are closed. It seems from the visuals that these shouldn't appear ever. The issue would be 2 sided: how can this show up in the first place, and how come once it's shown it stays there even when it's closed.
Do you see these windows normally in AltTab? I
No, not at all!
And I absolutely agree with this:
how can this show up in the first place
I think they shouldn't show up in the first place.
and how come once it's shown it stays there even when it's closed.
To be clear, I wrote:
I even closed all PhpStorm windows so that only the "project chooser" / welcome screen would appear and they would still be displayed via AltTab.
What I mean with this is, the "process" of PhpStorm was still present all along. It's just _within_ the various open project windows have been closed.
Granted, I know nothing technically about all this but I can imagine that unless the process disappears, there are still some dangling references. So that even if I close the "main window" of a project, the overall java process is still there (and AFAIK PhpStorm & friends run in a VM which only shuts down if you truly completely quit PhpStorm, not just when I close a project window).