If "Idle"-status overrides a personalised status, then I think that's a good thing.
I don't realy see the problem here. Personalised statusses aren't "Idle"-states or anything. Personalised statusses are statusses (just like the build-in ones) that you can use for other things like an "idle"-state. So, there is a difference there and thus this is where the confussion comes from...
Let me put it in another way: you have "online", "busy", "brb", "appear offline", ..., and then you have some personalised statusses with your own tags. All these statusses, doesn't matter if they are made by yourself (personalised status) or not (build in messenger statusses), they all can be choosen to kick in when you are "Idle".
Messenger has an "idle"-indicator of it's own and this will only set you to the status "away" after X minutes. See
tools > options > personal.
Messenger Plus! has also an "idle"-indicator, which will set your status to anything you like (including personalised statusses). This will also kick in after the X minutes. See
plus! > preferences > general options > miscellaneous.
(note that the detection of being "idle" that Messenger Plus! uses is somewhat different then that of what Messenger uses.)
Soo you see, "personalised statusses" are just some custom made names for statusses and have nothing to do with the state "idling".
In a schematic it would look like:
You are signed in and your status is:
online
busy
away
appear offline
...etc...
persostat 1
persostat 2
persostat 3
...etc...
Messenger detects you're using a full screen app. and can set your status to:
busy
Messenger detects you as "idling" and can set your status to:
away
Messenger Plus! detects you as "idling" and can set your status to:
online
busy
away
appear offline
...etc...
persostat 1
persostat 2
persostat 3
...etc...
I hope this explaination was suitable for you
PS: Messenger has also a "busy"-indicator, which will set you to the status "busy", if it detects that you're using a full-screen application.
See
tools > options > personal.