I've been having a problem as of late, since upgrading to X3 Studio from X3, with my transport not starting and stopping with my space bar. Until today I simply hadn't put two and two together, but the answer is Blue Tubes.
 
Anytime I insert or open a Blue Tube effect, once I'm done my work with the processor of choice, closed it, and moved on to other things, I no longer have any ability to start or stop my transport. Usually the Stop button is even grayed out after this as well, so I have to hit the mini-bar thingy under the transport to stop and rewind, or the marker snapping module.
 
On one or two occasions I did regain control with the keyboard, but I am not certain what allowed this. Normally, a full restart of Sonar X3 Studio is required.
 
Another thing of far less importance I've noticed is that my track icons become pixelated, but I'm not sure if this is happening exactly in association with any other process or action.
 
Anybody else experience this, and what the heck can I do about it?
 
 

Did you accidently press the give all keystrokes button?  That is the first thing that comes to mind.
 
@

I have never had to press that for any reason, in any version of a Cakewalk DAW. I know what it does, but since I really only use my keyboard to name presets I save, and to hit play/stop, I've never once had to push that "button" on the top right of the plug-ins.
 
So no, I did not do that. Besides, even if I had, wouldn't that only apply when the plugin was open? Also, this is not a one-time event. This is in every project, with any Blue Tube processor, on any track. Same thing happens every time.

I've had something similar, esp the pixilated track icons.
But the worst offender was Blue Cat - in fact anything by Blue Cat, freeware, demo etc.
Whenever I tried to minimize ANY Blue Cat plugin - ALL of X3 graphics would disappear, I mean EVERYTHING, and yet the audio kept on playing! The only way to get X3 back visually was to reboot - pita.
Blue Cat got flung.

That sucks Bonjo, 'cause frankly, I love the processors. If I had to get rid of my Blue Tube ones (that's what I'm talking about, not the Blue Cat you're referring to, although maybe that was just a mistype?), I'd be rather upset, since they, and ProChannels, are about the only things for which I upgraded.