When assisting another user with PDF printing, I noticed a small quirk with the "Manage Custom Sizes" option when setting up paper sizes. It appears there are two dialogues in the various print options, one of which isn't as featured as the other.

Starting with the Print option from the File menu, the Print dialogue (Print Dialogue.png) has a paper selection drop down accessible immediately. If I select "Manage Custom Sizes" I am presented with a new window (Print Dialogue Manage Sizes.png). This window doesn't allow me to add a papersize from the builtin list.

However if I close this window and click Edit Page Setup, I am shown another paper selection drop down. Selecting Manage Custom Sizes here I am shown a slightly different window to the previous one (Page Setup Manage Sizes.png). If I click the + now, I can select papersizes from a builtin list.

Both these windows should have the same functionality.

Lastly, it seems impossible to arrange the custom papersizes in alphabetical or numerical order in the second window. It doesn't matter which order they are added to the list, they seem to jumble up. This can be seen in the screen captures attached. The window that wont permit papersizes from a builtin list does stay in alphabetical order, but the other wont. The two lists do appear to be linked together.