Do you find the current one not adequate? The look of the new one would be more classic. It would have the usual search function and a better way to display code.

Draw a border for any fields and possibility for setting a padding property from field to control container

A mode switch whereby the category gets hidden if it turns out to be the only one. Ideally (might be a separate request) property names would line up to the left without leaving the indentation for the (missing) category.

the ability to add a dependency(attribute?) to a property so that when another properties values meets a certain criteria it becomes hidden/read only or has some other state altered.
example:

public bool toggle;
[Dependency("toggle",Comparison::Equal,false,StateChange::ReadOnly)]
public int Width;

width would be read only if toggle is false

Slider feel properties currently have a free text section to the left. it would be better if you could choose for this to be a numeric up/down field instead.

Currently SFPE automatically cycles back to the leftmost field when you finish the rightmost one.
This seems reasonable-ish when you are, e.g. doing HH:MM:SS, and are cycle through 3 or more fields. However, when there are only two, HH:MM, it is annoying.

This is a kind of experiment here, and I would like to see if my customers / visitors want to express their needs and wishes. Vote on the best ideas and give your thoughts in the comments. Thank you. Nicolas