View pane takes too many seconds to display a .cs file

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.

Does that still happen if you disable everything under Preferences / Viewer / Plugins except the text plugin?

If it doesn't, please re-enable them a few at a time to work out which one is causing the slowdown and let us know what you find so we can suggest the best solution.