I have been using alot of the core Flash UI Components lately, while creating a new online application and i have found that i have wasted alot of time, fiddling around with silly little errors and mishaps in the code of the components which is annoying!
For example i wanted to use the scrollpane component to display content created on the fly with actionscript, as opposed to attaching something from the library or loading an external movie/image and this was the hugest pain in the rear end to get the scrollbar to recognize the content, when really it should be a simple task. Then there is the SplitView component, what a pain in the arse it is, to display a tree component on the left hand side of the splitter and a scrollpane on the right hand side of the splitter and have the components resize 2 fit the space available correctly as opposed to scaling out of proportion, alot of changes need to be made to the code for this to happen, it would have been much easier to accomplish if the component provided an onResize event handler. Another example, the Scrollbar component probably my favourite in all the sets up until now lacks quality aswell, if you resize the textfield it is attached to and then resize the scrollbar using setSize, the maxscroll property of the textfield isnt re-calculated and thus the scrollbar doesnt scroll the text correctly. If i place a tree component on the stage and set it to the size of the stage, why doesnt it display in the movie at that size? components are aimed at designers right? surely they want control over the size of things at the least. I think the components are great but i wish that the people who write them would actually think about where the component will be used and in which situations as opposed to just coding away a lump of functionality that when used in the real world is such a pain, people would rather write their own, project budget permitting.