However It would be great if it wouldn't disable the background mirc window while opened. You always have to clos/reopen it, when you need to copy/paste something from/to a mirc window.
Right click where? Once it's opened you can't click anywhere else... And the log viewer window itself doesnt have an "on-top" property in its context menu.
I don't see any reason for the log files dialog to be modal, but then again I don't see any reason for any of the other dialogs in mIRC to be modal (i.e., options, favorites, channel list, address book, online timer, colors, send file, etc.).