Error when targeting a group

I'm not really sure why, but I have a group of icons as a target and it doesn't work, shows this error:

Uncaught TypeError: Cannot read property 'style' of undefined
    at Object.getTargetCells (grapheditorxblock.js:123137)
    at grapheditorxblock.js:123064
    at Array.forEach (<anonymous>)
    at grapheditorxblock.js:123063
    at Array.forEach (<anonymous>)
    at Object.createEventHandlers (grapheditorxblock.js:123054)
    at grapheditorxblock.js:122962
    at Array.forEach (<anonymous>)
    at Object.install (grapheditorxblock.js:122954)
    at HTMLDivElement.<anonymous> (grapheditorxblock.js:122756)

I'm not really certain how to reproduce this yet, but what I did:

Make a group of 2 icons
Make a on hover action with that group as a target
Put the trigger node of the action in a different group.