Sorry for the delay in responding. We are aware of the issue and a bug has been filed against it. The only work around in the short term is to use the Settings dialog to increase the message timeout. Although I haven't done any investigation into it yet, I believe it is related to the maximum number of textures that are available in OpenGL 4 and a non-optimal communication between the server and the client about those textures.
As such, I expect that you'll find the "HUD Controls" and "All Textures" features to experience this slowness (in addition to the connection), but other features, such as "Active Textures", should be quick.
To help guide our OpenGL development and support, can you please let us know what features of OpenGL 4 you are currently using?
Thanks for the answer. I don't think it's OpenGL 4 fault only, because I have the same problems under OpenGL 3.3 with Radeon 4650.
As you say, slowest operations are connecting to application and enabling HUD controls, other functions (active textures or shader code) run rellativelly fast.
Currently, I use most of the OpenGL 3.3 functions with a few OpenGL 4 things (textureGather) but I'm planning to use more features (such as tesselation) in the future.
Still no improvement?