I can tell you that this may apply to some premium themes, too. I bought a premium theme but the theme developer use very small text size, some thing like 13, or 14 pxl. The lowest size should be 16 pxl, it's arguably the recommended default size. If you use too small font size, when links are created, especially in ordered or unordered list, you will experience "Clickable elements too close together."
For example: in this question, the tag list may experience this kind of error. The expression "asked 9 hours ago in Themes by PELock " also has small font size.
"Content wider than screen" errors are more likely to happen when you try to modify the layout, there are some objects that go beyond the normal viewport, or you are using images without dimensions