Thanks for replying, glad that it's on the radar already

When you place an item as a blueprint, you can now edit the properties of the item before it is actually placed. However, the moment the item is actually placed, anything you were editing about that item is reset and in some cases the window is closed.

For example, placing an assembling machine (or ...

If you put 300 processing units in a rocket (which is the max capacity) it shows up as 999kg/1 ton. This might be due to rounding since one stack is 333kg so it comes out to 999kg. Other items might have the same rounding error but I haven't tested it.