I have three effects in my effects bin, but only one can be enabled at a time.
 
If I enable a disabled effect, the enabled effect is disabled.
 
How do I make them all enabled?
 
It seems only one effect can be enabled at a time.
 
If I enable an effect in another track, all other effects are disabled.
 
This is now happening in all my projects???
I am on Platinum.
 
Solved:
 
I uninstalled and went back to X3.  In X3 all three effects would highlight blue, and all could be activated.  I could open all three effects interfaces at once.
 
Back to Platinum, all the effects stay gray except the selected effect which turns bright blue as before.
Even the non selected effects are still enabled and modifying my sound.  The active effects are just not all bright blue as before.
There is no visual indication an effect is enabled in Platinum.  Also, I can now open only one effect interface at a time.
 

Hi. I am not sure if I understand your problem, but maybe try unchecking recycle plugin window in Preferences (P), File, Vst Settings in Platinum. 
All the best.

The visual indication is a little different in Platinum, but you can still see which effect is enabled and which isn't. I also preferred the X3 look, it was clearer to me. As for having only one interface open at a time, this is called plugin window recycling and as Ken said this is now the default preference. You can change this in preferences or you can still open a new window by CTRL double clicking the second/third/etc effect.
 
Personally I got used to it and I enjoy the lack of clutter. It's really not that often that you need multiple plugin windows open simultaneously and you can still do it with CTRL when you do. 

Thanks.

This forum never ceases to amaze me.

I guess I preferred the bright blue indication for an enabled plug from earlier versions instead of th platinum light gray/ dark gray in Platinum.

I also understand the bakers logic in recycling the plug Windows even though I don't use a lot of plugs for my acoustic music.

Bluegrasser +1
 
I too went through the same frustration !!  I saw the highlighted blue enabled plugin after I installed Platinum and then noticed that the other plugins were grey, too thought they had become disabled.  I them noticed that there were two shades of grey, (not 50) LOL, in the FX Bin for my plugins.   After checking with the forum, I was enlightened as to why the plugins were grey and greyed out.   
 
I too wish Cakewalk would change this. It's somewhat confusing at times when you have a huge track count and many plugins inserted to be able to scan with your eyes and remember that light grey means on and dark grey mean off and blue means most recently selected.

My eyes are so bad that this gets me every time. Cakewalk please change and I will buy you a real ale!