Basically, the graphs dialogue will get a second option.

Where now only sensor selection is (right side), there will be two options (selectable by tabs), one for "Flex config" and one for "Any sensor".

Here is a preliminary view:

1. User can select an asset from a dropdown (assets are all assets in the same tree as the currently edited one). The flex-config of the selected asset is loaded in the background & stored in local storage
2. User selects a flex-config field (the list contains both flex-context and flex-model fields)
3. If it has content, that will be shown (simply the JSON or string)
4. The user can click "Add to XYZ graph", as usual.