I've upgraded to version 12.0
When I enable the View pane and click on a csharp file (extension .cs), it takes almost a full minute for the view pane to show the file. It shows 'myfile.cs (Loading)'.
While its loading, I can navigate using the folder tree pane. However, if I then click on another '.cs' file in the folder, nothing happens. Then if I try to do something else, DOpus is locked (unresponsive) until the loading completes.
Once the first file loads, other files with same extensions display almost instantly.
I think that the delay happens the first time (after my system boots) a file with a specific extension is viewed.
This behavior is new to version 12.
My system is Windows 7 Ultimate (x-64) with dual xeon processors (and 64GB ram) so resources are not an issue.