Issues with OMEdit and components from the PowerSystems library

[Francesco Casella]

Open PowerSystems.Examples.Spot.Introduction.Frequency in OMEdit and see:

• The Windows version of OMEdit (v1.10.0-dev-159-g4de9151) will hide the + and - navigation elements in the tree view of the Libraries pane on mouseover (just not nice, but see below). The Linux version (v1.10.0-dev.134+gb85235d) does it right.
• OMEdit shows all conditional signal inputs of voltage1 and voltage2 even if they are disabled (see #2081)
• double click on voltage1 to open the parameter dialog -- the Windows version of OMEdit will destroy the diagram layout -- the Linux version keeps the position of the icon in the diagram
• OMEdit shows the Scripting Error "error parsing unit VA"
• The voltage veff is in p.u., which is represented with "V/V", relative to V_nom, in the PowerSystems library. OMEdit proposes the alternative units "rad" and "sr"!?
• OMEdit does not propose alternative units for V_nom, just "V" -- "kV" would be nice.
• The angle alpha0 is shown with the SI unit "rad". OMEdit proposes to alternatively use "sr". Why doesn't OMEdit use or even propose the displayUnit "deg"?
• OMEdit proposes for the frequency f the alternative unit "Bq". f is bound to the parameter system.f. What is the meaning of changing the display unit of a variable name?

Once you got around all these things, you finally find out that fType_par is always disabled, independent of the actual value of fType_sys. It appears that OMEdit generally lacks the evaluation of parameters when rendering graphics or parameter dialogs, see #2661 and #4008.

Originally reported by @rfranke as a comment in #4008.