Avoid creating comboboxes

(closes #5568)

Several strategies in here:
- Move uiCombobox() from inside the render function to class variable
- Don't render stuff like the raw tag editor when it's collapsed
- Don't show as many fields/combos on hover
- Don't instantiate fields (like universal/more) until they're actually shown
- Bind the combo on enter selection not on update selection

modules/ui/fields/cycleway.js

@@ -57,7 +57,7 @@ export function uiFieldCycleway(field, context) {
             .call(utilNoAuto)
             .each(function(d) {
                 d3_select(this)
-                    .call(uiCombobox(context)
+                    .call(uiCombobox(context, 'cycleway-' + stripcolon(d))
                         .data(cycleway.options(d))
                     );
             });