Yes.

Haven't heard of 'town defense' before, but shielding, bubble (viking's term), inaccessibility (throne term), all same thing.

OK - yes, I see when you bring up boosts the group of shield items (8h, 24h, 3d, 7d) are all under the 'town defense' title.

Best you can do is 'B' (Boost shortcut key), scroll down really fast (touchscreen users have an advantage here) all the way to the bottom, etc.

If the shield is still up, it will be at the top of the initial Boosts window already.

You can also make one of the shield items a favorite, then click on the far bottom right button when you first get into Boosts.