Index and expression page - highlight region if no dataset collection selected after searching

[adkinsrs]

Currently if the user attempts to search without selecting a collection, a toast-like message (correctly) appears to let the user know to select a collection. But it would be useful to highlight the box they need to change ("is-danger" border) so they will know what to change.

[adkinsrs]

An example of what I think should happen. May some small help text under to say "this is required". I already have some CSS here

gEAR/www/css/common.v2.css

Lines 112 to 127 in 335197d

	.select.is-success select, .input.is-success, .textarea.is-success{
	border-color: #539400; /* overwrite default success for .select */
	}
	.select.is-success:not(:hover)::after {
	border-color: #539400; /* overwrite default success for .select */
	}
	.select.is-danger select, .input.is-danger, .textarea.is-danger{
	border-color: #942400; /* overwrite default success for .select */
	}
	.select.is-danger:not(:hover)::after {
	border-color: #942400; /* overwrite default success for .select */
	}

that will overwrite the default "salmon"-looking is-danger class coloring that we have in our SASS file for these situations with "select" objects

[jorvis]

For now I've implemented it with coloring only, but no separate label, which can be added later if needed. I tried a few views of it and it didn't fit well with the rest of the form.