.ws document from Finder renders extremely slowly

[Egbert-Azure]

• WordTsar GUI
• .ws document

Steps to reproduce

Locate a .ws document in Finder.

1. Right-click the document.
2. Select Open With → WordTsar.
3. Wait for the WordTsar splash screen to disappear.

After the splash screen disappears, the GUI initially displays only:
.Z with a blinking cursor.
Moving the cursor down causes .he and the beginning of the second line to appear.
After waiting for some time, more of the document gradually appears until eventually the document is displayed.
The document therefore appears to be loading/rendering incrementally rather than being displayed normally when WordTsar opens it.