Middle mouse button macro does not work?

[Bullpocalyps-draenor]

Hello.
So i started playing a healer class and i assigened a mouseover macro to my Renew spell to the middle mouse button.
When i hover my mouse over to a party member it does not work.
If i assign the macro to another button it works.
If i press the middle button with the macro assigned to it without targeting anyone it works (it only heals me, but the macro works).

Only when i target someone else (hover over) and press the mouseover macro with the middle button is when its not working.

This is the macro:
#showtooltip Renew
/cast [@mouseover,help,nodead][] Renew

Could anyone help me with this?
Or is the middle mouse button not allowed to be “customized” for mouse-over macros?

All this with blizz interface …no addons…i dont want addons for this

[Magiola-darksorrow]

I had similar issues (the same behaviour) when using extra mouse buttons (not exactly the same, so no clue if it’s related). Apparently WoW doesn’t handle “extra_mouse_btn_x” too well when it comes to Macros. So I assigned a normal character to that button in the software I got with the mouse.

So now the “extra mouse button 5” is [,] (comma) and it works like a charm.

[Benikage-burning-blade]

I use a slightly different macro style for mouseover spells that you could try:

#showtooltip
/cast [target=mouseover,help,nodead][]renew

this works fine on my healer assigned to both middle mouse and the 2 side mouse buttons.
worth a shot I think.