mGAP/JBrowse Issues 2

[bbimber]

In no particular order:

• In the variant search page, open the search panel. This should have one blank field. Click the 'common filters' and add a field. The existing blank field is retained - we should probably remove it.
• Do the above and hit submit. The first blank filter turns red because it's invalid (that's correct). however, when you remove it, the second (valid) filter gets shifted to spot 1 and it now turns red. We should re-calculate the valid status when changing filters.
• Do the above, clear the blank filter and apply. Now re-open the filter dialog. When applying a new 'common filter', it replaces the existing, rather than appending. I'm not sure why this would behave differently from the above; however, we should probably append to existing non-null filters, rather than replace them.