I can confirm the PR fixes the issue. Thanks!

@ercanozkaya Could you mark your test result in the issue tracker here https://issues.joomla.org/tracker/joomla-cms/46237 by using the blue "Test this" button at the top left corner, selecting your test result and then submitting? This makes sure that your test is properly counted. After 2 test, this PR will then be ready to commit. Thanks in advance.

I have tested this item ✅ successfully on 5270cef

I set test result manually for @ercanozkaya since he reported that the PR fixed the issue. RTC

I set test result manually for @ercanozkaya since he reported that the PR fixed the issue. RTC

This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/46237.

Thanks!

One thing to note is that this PR slightly changes when behaviour plugins execute. When they were loaded inside initialiseApp, the language was already loaded and the user’s editor was set. Now, that’s no longer the case. I don't foresee this being a problem, but it might still make sense to mention it in release notes.

https://github.com/joomla/joomla-cms/blob/5.3-dev/libraries/src/Application/CMSApplication.php#L783-L809#

One thing to note is that this PR slightly changes when behaviour plugins execute. When they were loaded inside initialiseApp, the language was already loaded and the user’s editor was set. Now, that’s no longer the case. I don't foresee this being a problem, but it might still make sense to mention it in release notes.

@Fedik Is this something which you could fix in this PR here?

@Bodge-IT @softforge If Fedir can't fix it with this PR: Would you then add something to the migration docs for the developers?

I will add note to manual later, the language available only afterInitialise event, it was always like that.

Thanks @Fedik for the fix and testers for checking.

I made PR for the manual joomla/Manual#536