Messenger Plus! does not depend on the e-mail client what Windows Live Messenger opens when e-mail button or WLM's own email notification toast window are pressed. CookieRevised already said this in a different way.
But what Windows Live Messenger opens for emails depends on what you did on a Windows account. I must give an example from my case here because I can't clarify it without an example.
I created a new windows account and started using Windows Live Messenger normally, and e-mail button of WLM used to open hotmail in Internet Explorer. But when I manually opened Windows Live Mail Desktop and signed in with it, my email button on WLM started opening WLMD anymore. And now I can't open my hotmail address in Internet Explorer from the button in my WLM.
And Basdub, you are right, even if my Windows Live Mail (the name of the latest version of WLM desktop,
[yes, update it Basdub http://ideas.live.com]) is default Mail handler in my computer, if I didn't write any internet address or a program path of a email client on my computer, Messenger Plus! Live opens Windows Live Hotmail in Internet Explorer
. Didn't really understand why? A bug? Maybe. However Messenger Plus! isn't notifying us for the Email client which she will open when her toast window is pressed in a tooltip in her External Email Wizard anyway. I mean, it is
not displaying any tooltip which is saying "If no address or program is entered here, Messenger Plus! Live will open your default email handler."