You aren't missing anything. This is the way it works. For what it's worth, it's also the way it worked in version 4 (I just looked to be sure).
What I might suggest is creating a new project so you get the option. Then after you record, copy the slides from the new recording and paste into the project you want.
And if you feel it should really be a selectable option, please consider submitting a Wish Form to alert the development team. Link is in my sig.
Helpful and Handy Links
yes thats what I did. Copy background... since I already had audio etc etc. Since the function has been implemented its really only for the development team to "unhide" these features when additional slides are being recorded. We will be adding some wishes for CP 5. My collegue tried cropping a project earlier today... :-) Cropping from a heigth of 768 to 765 led CP to believe the project was getting larger.
FWIW - I suffer from the same issue and applying the patch makes no difference.
No, but "File, Record New Project" works fine. I work with the original project open when I start the new recording. Then I just copy and paste. It works but it's not something Adobe should be proud of...
I can understand your frustation.
I believe the logic behind Captivate's behavior is that:
All slides inside a Captivate project have to be of same dimensions. Suppose you chose 640x400 during "record new project" and Captivate did allow you to choose an application region during "additonal recording" which was (say) 120x300, then it would not be quite clear as to how to make this content fit with rest of the project. Automatic rescaling might (most definitely will) bring in lots of visual artifacts (stretched/compressed images). Without rescaling the content might be acceptable for some and may be not for others in the context of the contents in rest of the project slides.
May be you should go ahead and log an enhancement bug describing what would be the most desirable automatic action that you would wish Captivate did when it captures contents of different dimensions.