Normally only one object is displayed in the map.
The trick is to click is five times or more on the HOME button. After clicking on the SHOW button in APT, the rectangle send by back by APT is stored by HNSKY as five lines in supplement 2. Any new rectangle by APT causes HNSKY to replace the five lines with new positions. By hitting the HOME button in HNSKY or (mouse popup, markes and lines, add marker) five new markers are placed as lines in the supplement. By doing so you protect the rectangle of being updated. So a new SHOW by APT will replace these five marker lines en not the five lines of the last rectangle. I didn't work out a better solution after 2017 September since I hoped I could work out a better solution with Ivo of APT.
1) Hit SHOW in APT.
2) Click on HNSKY top caption line to make it the active window for the keyboard.
3) Hit five or more times the HOME button.
Repeat above for each rectangle of the moasaic.
Alternatively could call up the supplement 2 (ctrl-2) in HNSKY and double the five lines of the rectangle or just add five lines. The rectangle is placed at the last line of the supplement.
It would be nice if APT could send the server add_frame command in addition to the set_frame command. This would avoid above trick.
Placed a request at the APT forum:
Hope this helps,