The above link takes directly to a related topic that highlights a problem that I had with Sunbird. This problem contributed to my becoming aware of Lightning. I now have a couple of questions about Lightning.
First, is there any significance to the fact that the problems discussed in the aforementioned topic that occurred with Sunbird do not occur using Lightning?
Second, what are the primary differences between Lightning and Sunbird, as I notice a significant difference in the size of the two applications? (I understand that some of the difference can be attributed to the fact that one is a stand alone program whereas the other is merely an extension, but does this explain the entire difference in size or are there more substantive differences?)