Inspecting items during combat is a pain, particularly in survivals where you often have to check them out quickly before they get deleted. There's a few reasons for this:

1) The delay before the popup appears, along with the animation time as it expands, means you have to wait a full second after highlighting an item before you can start inspecting it.
2) If an enemy crosses between you and the item the popup disappears.
3) If several items are close together it's difficult to highlight the right one, as the highlighted item is often different than the one you would expect from where your cursor is.

Problem 1 wouldn't be so bad (I can imagine someone sarcastically saying "Oh no, a full second! First World Problems!") except that in combination with problem 2 a stream of enemies will prevent you from inspecting anything behind it indefinitely. Problem 3 makes it worse, as if there's a small gap which would normally let you see what you want, you might end up inspecting the wrong item, and who knows when the next gap might be.

Possible solutions:
1) The animation should be tied into the "fast gameplay menu transitions" option; if it's activated, the popup shows up at full size immediately when triggered.

The delay before the popup is triggered is trickier; I can see it being annoying during combat if it were just removed entirely and the popup showed up whenever your cursor touched an item for a moment. One option would be to have a key that removed the delay either when holding it down or as a toggle (I can see advantages to either approach). Removing the delay should probably happen automatically during build phases, as during the build phases you're either looking at items or placing/repairing/upgrading defenses all of which disable item inspection anyway.

If you don't want to add an item inspection key I suppose you could leave the delay in during combat; as long as the animation and problem 2 were fixed it wouldn't really be an issue.

2) This one has an easy solution: just make it so only monsters within a fairly close distance (maybe several yards) make the popup disappear. This would allow you to inspect items from a distance instead of requiring you to risk your life going up to them, while preventing the popups from disrupting close combat.

3) It feels like the highlighted item is based on the first hit between the camera -> targeting reticle ray. This is easier to program but produces counter-intuitive selections. I think a better way would be to find the first intersection, then also find all further intersections within, say, fifty percent extra of the first intersection distance (so if the first object is x distance away, all intersections between x and 1.5x), and pick the item whose center comes closest to the targeting ray. This would keep more distant items from interfering with the selection while making it much easier to choose between items in a clump, and if you do want to see that distant item you can move a bit to the side and get a clear view.