Well, I found out a couple of things that might help you to give me some other suggestions. First, I was mistaken, and I did not have "always enable this toolbar's keys in listers" enabled in any of my toolbars at all.
Then I thought I'd turn off the background image on one of my custom toolbars, to see if it would switch faster. I rebooted the system, started Opus, and clicked the appropriate button on Main Programs to switch to that toolbar without a background image. Same result as always, it took about 10 seconds to switch. So, I Right clicked on that toolbar, selected Customize, and restored the background image.
Here's where it gets interesting again.... While I was still in Customize mode, over on the left I clicked the check box for my CD toolbar, and what do you suppose happened? It still took about 10 seconds for the toolbar to show up under the already opened toolbar, and I still got the "Not Responding" message. So, I tried it with another toolbar, the 'Games' toolbar. I checked that box in Customize, and same thing, took 10 secs to show up under the other 2 toolbars, and I got the message again.
I then un-checked those selected check boxes, and then I checked the exact same ones again, and they showed up almost at once, one under the other. No delay, no message....
So, does that help you to narrow anything down, with that new information? It's not a Button issue, and it's not a toolbar issue, if the same thing happens from the Customize menu, is it? Would that point to anything else, do you suppose??