"Target Forward" and "Target Back" actions must always be available

I was kind of excited to use the "Target Forward" and "Target Back" actions, putting them on my hotbar and then using them with my fancy mouse (mostly so I couldn't bind them to my mouse wheel - you can push the wheel itself left or right for extra buttons). I wanted it like this so I could further use the mouse wheel for Alt+ and Ctrl+ actions for those same keys.

Unfortunately, I had to put it back to Tab and Shift+Tab, because you can't use "Target Forward" and "Target Back" while performing other actions. What? This defeats the entire purpose of having those actions. It's quite likely I want to target something different while I'm attacking the first thing. As a result, it's much more difficult to bind other actions to the mouse wheel, because "Alt+Tab" will not do anything you want, and I can't have the tab targeting rebound to a hotbar key (you can't bind multiple things to the same key assignment).

Why is it designed like this? Please make "Target Forward" and "Target Back" usable at all times, just like tabbing through targets.

This should be fixed... until then you can add the following Macros.
.
Target Back
/micon "Target Back" General
/previoustarget

Target Next
/micon "Target Forward" General
/nexttarget

These should not display the "Can't not use while casting" error when clicked/triggered. Add these to there proper place so your hotbar and use them as you would have the standard "Target Back" and "Target Forward" buttons.