Can Firefox at least allow the same bookmark to be in both the drop down folder structure once and in the bookmarks toolbar once as well?
I suppose there is some 'logic' in disallowing duplicate bookmarks in the drop down folder structure, and I know the 'one bookmark' restriction is several years old and related to tags, which I don't use. But it often happens that I find myself going to one or several web sites frequently over a limited period of time. It was very convenient with IE to duplicate those 'high use' bookmarks in the menu bar for an intermediate period. With IE, I did not have to delete those bookmarks in the regular drop down bookmark folder structure in order to add them to the menu bar, and then later on have to reverse that process so as to have the bookmark somewhere in the folder structure, given that I was deleting the toolbar bookmark. I don't want to use a sidebar. In other words, bookmarks chosen for my menu bar were functionally dynamic, so to speak, and wonder if the trade-off for tags remains generally a good idea.
You can duplicate bookmarks, that is no problem. If you right click a bookmark you get an option to copy and can then paste it to another folder. You may not wish to do that with too many bookmarks or the numbers are going to double.
The bookmarks menu has changed a few times recently. I am in Firefox 32 at present and the dropdown content from the bookmark menu icon adjacent to the bookmark star show much the same as the sidebar.
Icons for folders are not shown in the dropdown. Whereas the sidebar subfolders are inline and underneath the icons the menu folders expand alongside alternatively left and right as you drill down.
You may have discovered the bookmarks toolbar may of course have folders or nested folders, and once it overflows it extends from an arrowhead as a dropdown listing.