All of the ideas within a given Topic are saved together in a single file. Whenever you switch Topics, Idea Keeper automatically saves all of the ideas in the current Topic and then reads in all the new ideas. You cannot access ideas from a Topic unless that Topic is active (displayed in bold, red type in the left list of the Organizer Window).
There is one exception to this - the Global Idea. This idea is stored as a separate file and is available regardless of which Topic is active. Whenever you change the Topic Folder, the Global Idea is not affected.
All Topics are stored inside the Topics Folder. By default, Idea Keeper creates and uses a folder called "Idea Keeper Topics ƒ" inside the Preferences folder as the Topics Folder. You can choose any folder to be used as the Topics Folder by selecting "Change Topic Folder..." from the Topic menu.
If you delete a Topic file from the Topics Folder while Idea Keeper is active, this can create an error. If you add a Topic file to the Topics Folder, it will not be available in Idea Keeper until you quit and restart the program. It may be easier to directly import the Topic (via the Import menu or dragging the Topic file into the Organizer Window or onto Idea Keeper's icon in the finder).