Update class RenderContentProxyBox

lib/src/widgets/box.dart

@@ -13,7 +13,7 @@ import '../models/documents/nodes/container.dart';
 abstract class RenderContentProxyBox implements RenderBox {
   double get preferredLineHeight;
 
-  Offset getOffsetForCaret(TextPosition position, Rect? caretPrototype);
+  Offset getOffsetForCaret(TextPosition position, Rect caretPrototype);
 
   TextPosition getPositionForOffset(Offset offset);
 
@@ -21,6 +21,13 @@ abstract class RenderContentProxyBox implements RenderBox {
 
   TextRange getWordBoundary(TextPosition position);
 
+  /// Returns a list of rects that bound the given selection.
+  ///
+  /// A given selection might have more than one rect if this text painter
+  /// contains bidirectional text because logically contiguous text might not be
+  /// visually contiguous.
+  ///
+  /// Valid only after [layout]
   List<TextBox> getBoxesForSelection(TextSelection textSelection);
 }
 

lib/src/widgets/proxy.dart

@@ -104,14 +104,12 @@ class RenderEmbedProxy extends RenderProxyBox implements RenderContentProxyBox {
   double getFullHeightForCaret(TextPosition position) => size.height;
 
   @override
-  Offset getOffsetForCaret(TextPosition position, Rect? caretPrototype) {
+  Offset getOffsetForCaret(TextPosition position, Rect caretPrototype) {
     assert(
         position.offset == 1 || position.offset == 0 || position.offset == -1);
     return position.offset <= 0
         ? Offset.zero
-        : Offset(
-            size.width - (caretPrototype == null ? 0 : caretPrototype.width),
-            0);
+        : Offset(size.width - caretPrototype.width, 0);
   }
 
   @override
@@ -275,8 +273,8 @@ class RenderParagraphProxy extends RenderProxyBox
   double get preferredLineHeight => _prototypePainter.preferredLineHeight;
 
   @override
-  Offset getOffsetForCaret(TextPosition position, Rect? caretPrototype) =>
-      child!.getOffsetForCaret(position, caretPrototype!);
+  Offset getOffsetForCaret(TextPosition position, Rect caretPrototype) =>
+      child!.getOffsetForCaret(position, caretPrototype);
 
   @override
   TextPosition getPositionForOffset(Offset offset) =>