This is a new feature in VX.2 when editing local symbols such as block symbols. In prior releases any changes were committed to the schematic as soon as you closed/saved the symbol, now you need to manually commit the changes using the File - Update Symbol in Design option or Discard the changes using the option below this. The red 'star' indicates the symbol is being changed or has been changed but those changes not committed yet.
many thanks for your response.
We use VX.1 It seems that this functions is already available at this release.
At first I was confused because I tried to use the UPDATE SYMBOL IN DESIGN option in the schematic editor. But this option is not available in the schematic editor.
But after starting the Symbol-Editor by using the EDIT LOCAL SYMBOL option, I find the Update function in the file menu .
Thank you very much for your help.