dc.js - d3-tip on dc-js chart disappears upon filtering over 0-valued group -

i have number of graphs, simplicity take this example on jsfiddle, there brush-on graph, bar chart keyed on time , row chart keyed on categories. in addition, use d3-tip library tooltips (in link above simplified version of tip).

in order avoid creation of bar-row in rowchart, used fake-group outlined in faq of dc-js (and here well).

the fake group works well, not displaying c category on row chart.

however, if brush on months 0 data, when reset filter (just click anywhere filtered region on brushon chart), d3-tip on row chart disappears.

notice if group created without fake-grouping-function, problem not arise.

• any explanation why happens?
• how avoid (without loosing remove_empty_bins)?

although can use dc.js , d3.js interchangeably, , dc.js intentionally "leaky abstraction", things go better if them idiomatic dc.js way.

i have 2 suggestions:

1. apply tooltips in response dc.js events reapplied when new graphical objects created (or re-created).
2. use chart.selectall instead of d3.selectall when modifying charts.

okay, #2 has no bearing on question, scope selects better it's harder them miss chart or accidentally modify stuff elsewhere in page.

implementing #1 looks this:

month_chart.on('pretransition', function(chart) {   chart.selectall('rect.bar').call(month_tip)     .on('mouseover', month_tip.show).on('mouseout', month_tip.hide); }); loc_chart1.on('pretransition', function(chart) {   chart.selectall('g.row').call(loc_tip)     .on('mouseover', loc_tip.show).on('mouseout', loc_tip.hide); }); 

the pretransition event fires right after render or redraw, it's best moment manipulate dc's elements. better running code globally. set up, call dc.renderall(), allow renders , redraws take care of later on.

in particular, when bars added in when remove_empty_bins stops removing them, these events pick them , re-tip them.

fork of fiddle: https://jsfiddle.net/gordonwoodhull/5fel3gko/4/