Fix for errors when selecting text in a non-scrollable editor

lib/src/widgets/raw_editor/raw_editor_state_selection_delegate_mixin.dart

@@ -63,7 +63,9 @@ mixin RawEditorStateSelectionDelegateMixin on EditorState
     final localRect = renderEditor.getLocalRectForCaret(position);
     final targetOffset = _getOffsetToRevealCaret(localRect, position);
 
+    if (scrollController.hasClients) {
       scrollController.jumpTo(targetOffset.offset);
+    }
     renderEditor.showOnScreen(rect: targetOffset.rect);
   }
 
@@ -77,7 +79,9 @@ mixin RawEditorStateSelectionDelegateMixin on EditorState
   // `renderEditable.preferredLineHeight`, before the target scroll offset is
   // calculated.
   RevealedOffset _getOffsetToRevealCaret(Rect rect, TextPosition position) {
-    if (!scrollController.position.allowImplicitScrolling) {
+    // Make sure scrollController is attached
+    if (scrollController.hasClients &&
+        !scrollController.position.allowImplicitScrolling) {
       return RevealedOffset(offset: scrollController.offset, rect: rect);
     }
 
@@ -102,12 +106,17 @@ mixin RawEditorStateSelectionDelegateMixin on EditorState
 
     // No overscrolling when encountering tall fonts/scripts that extend past
     // the ascent.
-    final targetOffset = (additionalOffset + scrollController.offset).clamp(
+    var targetOffset = additionalOffset;
+    if (scrollController.hasClients) {
+      targetOffset = (additionalOffset + scrollController.offset).clamp(
         scrollController.position.minScrollExtent,
         scrollController.position.maxScrollExtent,
       );
+    }
 
-    final offsetDelta = scrollController.offset - targetOffset;
+    final offsetDelta =
+        (scrollController.hasClients ? scrollController.offset : 0) -
+            targetOffset;
     return RevealedOffset(
         rect: rect.shift(unitOffset * offsetDelta), offset: targetOffset);
   }