I have a
drag a button on to the view
Then, in the hierarchy column on the left, ensure it is at the bottom. That means it will be in front of everything else.
So, if necessary move it so it is in front of (ie, below in hierarchy) the collection view.
Note that there is absolutely no problem, at all, with putting one control "in front of" the other (i.e., so that it "blocks" you from seeing all or part of the other one).
If you had a problem doing this, you've made a trivial mistake. For example you may have dragged the new button "into" the collection view, rather than as a "sibling of" the collection view. Hope it helps.