model component IDs clash, causing unexpected behaviour

[jbudynk]

Say one saves a model to a .json file, and the component IDs are m5, m6, m7, and m8. Then this person adds 5 new model components to the Fitting Tool. That last component will also be called "m5", thus wiping out the old "m5" loaded earlier.

To reproduce:

• load pks1127-14 from NED
• open the Fitting Tool
• load this Json file. These components are FROZEN. Keep them frozen. Evaluate the fit from the Plotter to see what it looks like.
• add 4 new components (powerlaws, broken powerlaws, whatever).
• set the fitting range from gamma to far IR (~1e7 Angstroms)
• Do a fit, for example m5 + m6 + m1 + m2, where m5 and m6 are old components, and m1/m2 are new components.
• now add another new component. This one will be m5. Set the model expression to m5 + m6 + m1 + m5.
• fit

You should see component 5 (in the radio part of the spectrum) has completely changed shape, if not disappeared entirely.