There are a number of Tooltips for many of the controls. For example, choose the Positions page, move the cursor over a callsign in the list, and you will be told to right click for a menu. Or try the Track page, where the tooltip will appear that will aid you in what can be done, such as double-click to add to the Track list. Not all controls have Tooltips yet.

APRSA4 always writes a file called APRSa4.Dat on exit and every 60 seconds while the program is running. This way, if the computer crashes or something else happens, the program will resume with no more than 60 seconds plus the time to restart the program, of data lost. APRSA4 also writes a file called APRSa4.Set which contains user data for the program which includes callsign, desired port selections, map settings, etc. Ypu can also save these files under your own chosen name, alowing you to have different setups. If these files are deleted, the program will have a "fresh" start.

To delete data from the Positions, Bulletin, Traffic and Status pages, right click on the item(s) you want to delete, and select delete from the menu. To delete multiple items, click on the first item, scroll to the last item, press and hold the shift key and click, then right click and choose the Delete option.

APRSa4 as it is first set up can hold about 4000 position reports, or WSS equal to 5 MB.  Note that it only keep unique reports.  For fixed stations, only one report is kept.  Once this is exceeded, the program will start to produce errors. You can Archive to Disk specific stations, delete specific stations with might have many reports, or delete the APRSa4.Dat file. I'm currently running with 10 megabytes as my wssize setting and have 1745 positions for unique callsign and objects, and 6956 unique position reports. Do not edit any other key in the INI file.

The number of reports that the program can support can be increased.  In the aprsa4i.ini file in the Windows directory, add or change the following entry:
[config]
wssize=xxxxxxx

Where xxxxxxx is the number of bytes that APRSa4 requests from windows at startup.  If you have enough ram/virtual ram, you can make this what ever Windows will support.  Currently, the default is 5000000.  Try increasing it to 10000000 and the start the program.  Check the About menu item and the about of available ram will be displayed (Available APL memory).  Keep in mind that during execution of certain algorithms in APRSa4, this number may actually only be half of the displayed value.  If the available memory is insufficient to complete a given task, a warning of WS FULL will be displayed.  At that point, either delete position reports, "filter" them, of archive them to disk to regain some free ram.

Gating of Internet data is disabled if the program is in HSP or Pico mode.