If i open too much windows i can scroll through it only with alt key pressed. Why? Can i change this behavior ?
Xorg
KDE (kubuntu 24.04)
With all programs, but more often i see it with firefox.
Task Manager > Configure icons only Task Manager > Behavior > Mouse wheel.
There is option to scroll between the open windows when cursor is hovering the icon on the task bar, but when hovering the windows list scrolling only works with the pressed alt…
Hi - if I’m understanding what you’re seeing correctly, it sounds like there are enough windows open for a single application to make its window thumbnails need to scroll horizontally - but that scrolling the mouse wheel up and down doesn’t do that?
If so, it sounds like you’re running into the following issue: 448504 – Horizontal scrollviews (e.g. Task Manager Grouped task tooltips with a bottom panel) cannot be scrolled horizontally using a vertical wheel - note some of the implementation challenges mentioned in the comments there, and a duplicate bug report that specifically mentions holding down Alt as a workaround as you’ve already been doing.
Can i change it to scroll without holding alt key somehow ?
I’m not aware of an immediate way to do that, unless you have a mouse that also has a horizontal scroll input on its wheel. Part of what some comments on that bug report were about are the tricky things to account for when trying to build in standard logic there.
Having said that, I’m sure someone somewhere has an idea for how to hack together a method using modifications to how mouse input is received or something - so I’m sure it’s not impossible, just difficult 
Yeas, I see, thanks)