fix: correct selection while scrolling

Author: chiarfe

lib/src/editor/editor.dart

@@ -984,19 +984,21 @@ class RenderEditor extends RenderEditableContainerBox
 
     if (position.offset < _extendSelectionOrigin!.baseOffset) {
       _handleSelectionChange(
-        TextSelection(
+        DragTextSelection(
           baseOffset: position.offset,
           extentOffset: _extendSelectionOrigin!.extentOffset,
           affinity: selection.affinity,
+          first: true,
         ),
         cause,
       );
     } else if (position.offset > _extendSelectionOrigin!.extentOffset) {
       _handleSelectionChange(
-        TextSelection(
+        DragTextSelection(
           baseOffset: _extendSelectionOrigin!.baseOffset,
           extentOffset: position.offset,
           affinity: selection.affinity,
+          first: false,
         ),
         cause,
       );
@@ -1055,10 +1057,11 @@ class RenderEditor extends RenderEditableContainerBox
       extentOffset = math.max(fromPosition.offset, toPosition.offset);
     }
 
-    final newSelection = TextSelection(
+    final newSelection = DragTextSelection(
       baseOffset: baseOffset,
       extentOffset: extentOffset,
       affinity: fromPosition.affinity,
+      first: toPosition == null || fromPosition.offset <= toPosition.offset,
     );
 
     // Call [onSelectionChanged] only when the selection actually changed.

lib/src/editor/widgets/text/text_selection.dart

@@ -498,22 +498,24 @@ class _TextSelectionHandleOverlayState
 
     final isNormalized =
         widget.selection.extentOffset >= widget.selection.baseOffset;
-    TextSelection newSelection;
+    DragTextSelection newSelection;
     switch (widget.position) {
       case _TextSelectionHandlePosition.start:
-        newSelection = TextSelection(
+        newSelection = DragTextSelection(
           baseOffset:
               isNormalized ? position.offset : widget.selection.baseOffset,
           extentOffset:
               isNormalized ? widget.selection.extentOffset : position.offset,
+          first: true,
         );
         break;
       case _TextSelectionHandlePosition.end:
-        newSelection = TextSelection(
+        newSelection = DragTextSelection(
           baseOffset:
               isNormalized ? widget.selection.baseOffset : position.offset,
           extentOffset:
               isNormalized ? position.offset : widget.selection.extentOffset,
+          first: false,
         );
         break;
     }