From our own popup items e.g the tool settings panel, layers panel etc, you don't need to tap to dismiss, you can just start painting and the menu will close. Alternatively, if you the button in the toolbar for opening that menu, that will also close it. We implemented this to avoid people needing to specifically dismiss the item with an extra tap if they didn't want to. Exceptions to this are the gallery and reference image dialog as they use Apple's menu system. We may revisit this in the future though, thanks for the feedback!
Resident Bug-Hunter and Support Guy