only draw visible full line background instead of maximal possible width

src/ui/bigtext/bigtext.py

@@ -520,11 +520,9 @@ class InnerBigText(QWidget):
 
         for highlight in highlights:
             if highlight.is_highlight_full_line():
-                left_offset = -1 * self._left_offset * self.char_width
                 y1 = y_line_offset - self.char_height + self.char_height / 7
                 height = self.char_height
-                full_width = Settings.max_line_length() * self.char_width
-                rect = QRect(round(left_offset), round(y1), round(full_width), round(height))
+                rect = QRect(0, round(y1), self.width(), round(height))
                 self.highlight_background(painter, rect, highlight.get_brush_full_line())
 
         for highlight in highlights: