Discord: Jazon#0745
Link to files: https://mega.nz/folder/75c1EThD#oxI4N...
SOLUTION:
protected override void DrawPropertyLayout(GUIContent label)
{
original = this.ValueEntry.SmartValue;
CreateRectMatrixTable();
this.ValueEntry.SmartValue = original;
this.ValueEntry.Property.MarkSerializationRootDirty();
}