Child list not complete and Custom Field child Multivariant not saved

[Geppux]

VM 3.0.9 - Joomla 3.4.4

Hi, I have a product with 105 child and I need to put in order the child list; usually I go in the parent where are listed the childs (the tab after the images of the product) and I give the order I want to display, but in this case are listed only 51 childs... how can I order also the others that are not listed? is it a bug?
Thank you.
Giuseppe

[Geppux]

I solved starting the ordering from 200 and making 51 products at time (giving high numbers to the first 51 products they went  at the end of the list and appeared the products that were not visible) but I have another problem... now when I go in the parent product to set the child multivariant when I try to save it , nothing is saved and the page returns to the virtuemart control panel... Please Help me, I made products with child multivariant many many times but never happened this, what I'm doing wrong , why the settings are not saved???
Thank you.

VM 3.0.9
J 3.4.4