Overlapping template selection box in Firefox 22 on Linux
When templates do not have a defined width the blue selection box extends the whole width of the window, regardless of whether the template does. This means that in some cases, e.g. at [[Where Does This Door Go]], the transclusion editor icon is displayed not on top of the template.
More seriously it also means that smaller templates to the right of larger ones are difficult of impossible to access because they are completely covered by the other template's selection box. At the same article, the "Professional ratings" translcusion is difficult to select (you need to click it in line with the slug between the templates on the left) and the tooltip icon does not appear.