I can't reproduce that behaviour and if you somehow managed to it'd almost certainly be a bug. Slashes are perfectly acceptable in dialog names:
dialog t/x {
size -1 -1 300 300
}
on *:dialog:t/x:init:*:{ echo -a t }
/dialog -m t/x t/x
Did you think there was an extra colon before the slash or something?
Edit:
Edit: Or if he's participating in an April Fool! (g)
Haha! Damn
Mentality Note: I cannot desribe the joy of refreshing the page and viewing your edit. I can almost see the look of "oh it just dawned on me" look on your face. <3