Hide system properties has two problems

[mingaliu]

1. Seems all underscore fields are hided, which is not right. It should only hide _ts, _etag, _self, _rid, _attachments etc.

2. Press the button doesn't toggle the display, which give the feeling that is not working at all.

[gardebring]

Please see #38 for partial fix

[gardebring]

Regarding the other issue, I am not aware of a way to remove only system properties based on the fact that they are system properties.
The two ways I can think of is to go through all existing system properties (based on a list of string values) or simply omit anything starting with a _. Not sure where one could find such a list though, and it will be error prone as the azure docdb system evolves with new and or changes names for system properties.

[mingaliu]

Regards "The two ways I can think of is to go through all existing system properties (based on a list of string values) ", this solution is good enough. because adding new system property is a very very rare event and when that happens, we just update the DocDBStudio then.

I saw many user have their property starting with underscore _. So we can't just hide anything start with _.