Unable to find style 'DD ItemStyle' in skin 'GameSkin' mouseUp after trying to open the dropdown while on play mode (restarting fixes it)

[o0Ezequiel0o]

2026-04-29.01-27-22.mp4

[AlexeyTaranov]

Can't repeat(
Can u send more information:
I see Windows, Unity 6.3.

Can u try to delete library? (sometimes editor can have damaged editor styles or something else)
Update to higher unity version?

Do u have additional plugins? (maybe odin or other ui inspector plugins). Can u try to disable and test it?
Can u send me full callstack? (its can help with check unity sources)

Thanks for reply!

[o0Ezequiel0o]

Can't repeat( Can u send more information: I see Windows, Unity 6.3.

What more info do you need? that's like the only 2 things i know of lol

Can u try to delete library? (sometimes editor can have damaged editor styles or something else) Update to higher unity version?

I've deleted libraries like 3 times already as sometimes the problem sometimes doesn't get fixed when opening it back

Do u have additional plugins? (maybe odin or other ui inspector plugins). Can u try to disable and test it? Can u send me full callstack? (its can help with check unity sources)

I don't really have any other plugins outside of unity at all

Unable to find style 'DD ItemStyle' in skin 'GameSkin' mouseUp
UnityEditor.IMGUI.Controls.AdvancedDropdown:Show (UnityEngine.Rect)
SerializeReferenceDropdown.Editor.Dropdown.SerializeReferencePropertyDrawer/<>c__DisplayClass32_0:g__ShowDropdown|5 () (at ./Library/PackageCache/com.alexeytaranov.serializereferencedropdown@6b83e9a3c62d/Editor/Dropdown/SerializeReferencePropertyDrawer_UIToolkit.cs:148)
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

(same message with headerStyle, itemStyle, defaultLineInspector, etc)

Thanks for reply!

I will try now with a different version, i'm using 6.3 LTS because it's long term support but i will try 6.4 if you want an higher unity version

nvm unity seems to seem throwing errors when trying to download a new version, that's weird

[o0Ezequiel0o]

For some reason unity is not letting me download any version but i kept trying to delete the libraries and it seems to still be broken now and i can't fix it.

If you wanna try the project it's here https://github.com/o0Ezequiel0o/Project-Abilities (should be very lightweight as it has less than 1mb of sprites)
There are a few things that use this property drawer (skills/ability/abilities) is an example where modules use this

[o0Ezequiel0o]

Tried on an another unity version (6000.4.5f1) and it still happens, had to reinstall unity hub because it wasn't working

when i'm selecting my scriptableObject (this one has a list with serializeReferenceDropdown attribute) module list and then i click play and then try to edit it it just fails to load any of those elements and ends up permanently broken until reloading the library folder

[o0Ezequiel0o]

I ended up finding the problem and I almost went insane (if I'm not yet), not exactly where the problem is in the code or anything like that but what actually ends up breaking it.

Right now I only know that whenever I go into one of my scenes (which have the cinemachine stuff) and run it, it breaks the dropdown menu permanently and it throws those errors.

I tried cloning my scene and opening and it still gave errors, then I

tried to remove the cinemachine brain from the cam and opened the scene, ran it and no problems

Apparently it indeed was another package (I did forget as it was from unity's) so nothing unofficial here.

both changing scenes and running the scene was probably making cinemachine load something or change something I honestly have no idea how this happens as if it does something it should be on GUI or something but maybe that runs too whenever I change scene to something that has cinemachine brain component or when I go into play mode

I did a few tests you can see in the video:
-> ran scene, changed scene, ran other scene (none with any cinemachine component)
-> added stuff to the scene from the editor and run it (still no errors)
-> added a cinemachine component, it also adds the cinemachine brain to the camera you know the drill, no errors
-> ran with cinemachine component, throws errors

so my guess is cinemachine is touching some stuff that is changing or deleting those elements and it's breaking this

I replicated this then on a new scene, with a script that has a SerializeReferenceDropdown list variable inside a scriptableObject, and did the same steps, error still happened

If this is a cinemachine problem and not related to this at all, feel free to close this one.

Here i uploaded the one in a new project

2026-05-03.19-14-34.mp4

Got rid of all Cinemachine scripts & packages and it's working without errors.

[AlexeyTaranov]

Wow, its really complex problem. Thanks for full exposed problem - on this week i will try to repeat and fix it =(