Issue

Toast/notify text in CJK (double-width) characters disappears when overlapping underlying widget border (resize reproduces)

Example:

Expected:

The bug

When calling App.notify(...), the toast notification renders correctly at first, but some CJK (Chinese) characters inside the toast text disappear when the toast overlaps the border line (e.g. border: round grey;) of an underlying widget.

Key observation:

English/ASCII text is not affected.

Only Chinese Han characters (double-width) are affected.

The missing characters occur exactly where the toast overlaps the underlying border line.

The issue is easy to reproduce by resizing the terminal window (which seems to trigger the partial redraw/composition).

It looks like the underlying border is sometimes drawn after the toast (or a partial “damage” redraw happens), and for double-width characters, if one cell is overwritten the whole glyph becomes invisible.

Expected behavior

Toast/notify text should remain visible and intact regardless of what widgets are underneath (including borders). CJK characters should not disappear.

Actual behavior

CJK (Chinese) characters in the toast become invisible in the region overlapping the underlying widget border. ASCII/English text remains visible.