This is killing both me and the project.

We're working on a farly large project.

The code is divided in two parts.
One solution that holds all business layer projects (9 projects, some small
and some large)
One solution that holds the UI projects (6 project, 3 exe, 1 small control
library, 1 resource lib, 1 reporting lib)
Almost all the UI projects depends on one or more of the project in the
business layer solution. Thy are referenced by adding references to the
dlls.
(this is done to keep the solution as a somewhat managable size. The change
ratio in the UI projects is also mutch larger than in the business projects)

Compile time for both projects is no problem.

However, we have huge design time issues with our main client appliction.
Whenever you try to design a form, it takes forewer to load it.
Some test result:
Opening a user control (having 12 controls) with a newly opened solution
after a recompile:
20 sec
Second time opening, fast (a couple of sec)
Reopening after changing some little thing and then compile:
20 sec
Open a different control, and then reactivate the already open control.
20 sec
As we often do some quite small changes and the recompile, this is starting
to cost us huge amount of time and frustration.

Almost all our forms and user controls is inherited, if that might matter.

Does other share this experience?
Anyone has a clue about where to start to fix this issue?

Regards, TEK