Our product is probably going towards using our company’s common UI. This will probably mean re-writing its GUI in a more Web 2.0 manner, which is nice.
I noticed that in their sample page they use a tree that doesn’t display dotted lines that connect the dots. I asked the library developer if I can use our current tree implementation that does use dotted lines, and he said he doesn’t think that’s matter, but forwarded me to the usability guru of the company.
She said that from their experience, the dotted lines adds nothing to the tree usability and should be removed. I planned to say “do you know better than Microsoft” as I remembered Windows Explorer did display dotted lines, but when I took a look, I was amazed to find out that Windows Explorer in Windows XP no longer shows dotted lines in the folder tree (I’m pretty sure those lines were there in a previous version of Windows), and Outlook also displays a tree of folders without dotted lines. I guess this is the new convention of showing trees. There are some Microsoft exceptions for this rule, though. For example, the project explorer in Visual Studio has these dotted lines (from Visual Studio 6 until the recent Visual Studio 2005) as well as the advanced printer settings dialog.
Oddly enough, I can’t find any discussion about it on the web.