Hi when a block is deleted,can I reactivate it ,how can i do it? Thx

1) Use 'undo' button 2) Create new block, specifying edges

If you're using version 5.0 or above - deleting a block (without delete permanently turned on) simply moves the block into the VORFN part. So - you could also add the block back into the Part of interest by viewing the VORFN part and selecting the block to add back into the active Part.

I will try,Thanks!