I use the treebar in mirc. I connect to several servers, and open a custom window, which i hide.

The @window is opened in the first server window, which is correct. I'm in two channels on server1, so alt + 2, 3 takes me to them, and alt + 4 shows the @window which is hidden. In switchbar, alt + 4 shows me the next status window (of server2). Would be great if it could be fixed so alt + 4 takes me to status window of server2 in the treebar too.

I am unable to reproduce this issue here. In all cases I've tested, pressing Alt+N will take mIRC to the correct window.

In the situation you have described, if you minimize @window, amd then press Alt+4, mIRC will and should select the @window for both switchbar and treebar.

If you /window -h @window, the window will be removed from the list of both the Treebar and Switchbar and pressing Alt+4 will then select the second server window.

Alrighty, perhaps it isnt -h. This is how i open the window:
/window -dohl +dL @Window 950 67 134 300. After this, it's not hidden. If you use /window -h @Window, it will be hidden, and then press alt + 4, and it will be visible again, assuming you're connected to two channels on first network only, and no queries etc.

Alt+N has technically always behaved this way, though I can see how it can be an issue. I'll see if I can prevent this behaviour in the next version.

Awesome. Thanks :-)