Andrew is referring to the graphics window's dashboard. You have a show/hide annotation.
PTC did something weird with "Erase"... yes you have to "Delete" the annotation to have available for "show" again. Erase maintains the "showing" of the annotation in the detail tree of the drawings. Unfortunately, PTC has been blurring the lines between detailing in a drawing and annotating a model. It is a very inconsistent pool of muck when it comes to understanding what you want to show. It goes much deeper than that as well when you get into the Y14.41 3D annotation.
As for hiding the datum plane that has a datum tag assigned to them, I have already sent in many support requests and they continue to tell me this is expected behavior even though it is -very- inconsistent. Sometimes they will hide indefinitely as well once they are unhidden in a drawing. You will also find occasions where you get a fatal crash when manipulating the datum tag on the drawing. I already reported that one with the ability to reproduce the problem. Haven't heard back on this yet. But know that a fatal crash means lost work. File often!
We have a very long running thread on the PlanetPTC with regards to instability of Creo 2.0 drawings. It is better with M010 but overall, it still has a lot of shortcomings.
Overall, when you start getting use to the quirks, you can figure a way around all these things. Knowing about them up front helps a lot.
Have you learned about Relative Accuracy yet?
Indeed, Creo 2.0 M010 is quite a bit more stable than any of the previous releases. Obviously, PTC is bug-fixing Creo 1.0 as well so keeping up with the latest version is important. I know that Creo 2.0 F001 was very painful in drawings but M010 made it much more stable. It still has bugs though, and if you want to use datum tags (ASME versions) in Y14.5 (rather than Y14.41) mode doing detail drawings, it is still very buggy in Creo 2.0 and I suspect similarly buggy in Creo 1.0 since very little attention is being paid to detailing at PTC.
My end product is the PDF drawingso how I get there makes little difference. I completely dropped the Y14.41 capabilities and literally made a very comprehensive symbol to make datum tags on the fly for the drawing with the help of forum members. Similarly, all my GTOL features are notes. The only limitation I have found to date is composite feature control frames which I rarely need. If needed, I can make those as 3D annotation by assigning datum tags and using the GTOL menu.
By contrast, I do use the dimensions from the model in the drawing. I am still working on making the thread notes compatible with my drawings as well since this has changed form past methods (2000i). Short of the GD&T, my drawings are probably 90% associative back to the model. I still have trouble formating chamfer notes the way I want. Limit dimensions typically give me the most grief when it comes to display options.
We also recently found the issue with GTOL rounding as discussed on this forum. The answer from PTC support was less that satisfying and was in fact rudely truncated when I requested further information. Turns out Creo GTOL does not have all theoptions available per the standards. Again supporting the "work-around" GTOL practices on the drawing.
Depending on your company's policies with regard to drawing associativity, you will find that your "drafting policies" will likely end up being dictated by the tool. This, in my opinion, is unacceptable as I've always been taught that the tool should never limit your requirements. In my case specifically since I serve several clients each with their own interpretation of the standards. I must be able to output exactly what they dictate since "the customer is always right".
Edit: Creo 1 and Creo 2 are pretty much the same. Some menu items have been moved around. The help files are still -WAY- out of date.