Delete products from invoice without PDF rebuild?

I have an invoice which I would delete. I know, that first all the single entries (products/services) must be deleted.

How can I suppress the rebuild of the PDF for every delete command (which is useless in such a case)?

ndrosis told me, that we can make a lot of settings according to this wiki page: http://wiki.dolibarr.org/index.php/Setup_Other

In this case, the setting
MAIN_DISABLE_PDF_AUTOUPDATE = 1
=> Disable automatic generation of PDF each time we add/update/delete a product line (we can still build document by clicking on “Generate”). This option may increase interface speed on server with low CPU.

works fantastic. Exactly what I wanted.
Problem solved!