Best event for putting message into status bar?

FossiG_

Hello,

I am a little stuck on this or just don't see the wood for the trees:

In the OnMouseDown-event of an Addins.Tool-class I put a message into the statusbar using set_Message

ArcMap.Application.StatusBar.set_Message(0, "<myMessage>")

The message is momentary visible and disappears through another refresh-event I suppose.

I tried onUpdate to publish the message, but this event is called too often for my favor. onRefresh only occurs on changes of the map, which is too rare on the other side.

Could anybody put me on the right path, please. Thanks in advance.

Best regards
Fossi