With this version I have added the possibility to select multiple bookmarks and drag them around using the mouse. It was more difficult than I thought to implement this feature and a lot of code has been modified and added, but I think the result is acceptable.
I was tempted to increase the version number to 2.5.0 because I find this new capability very important, but dragging bookmarks one at a time was already present so I have considered this as an extension to that feature.
If the bookmarks you are dragging are not contiguous and siblings, when you will drop them they will become such. The bookmarks remain sorted from top to bottom independently from which of the bookmarks you press on to start the dragging gesture. This is what I think is the most reasonable way to manage multiple dragging but any hint is appreciated as usual.
I have also changed the appearance of the last bookmark followed in the viewer to appear as grayed, I think it can be useful.
Let me know your opinion and report bugs, thank you.
