not working in ff46: ReferenceError: prefs is not defined

[eMBee]

ReferenceError: prefs is not defined
Stack trace:
processWindow@resource://gre/modules/addons/XPIProvider.jsm -> jar:file:///home/.../.mozilla/firefox/....default/extensions/tabgroupsbtn@char101.github.com.xpi!/bootstrap.js:20:1
watcher@chrome://tabgroupsbtn/content/addon.jsm:91:7
runOnWindows@chrome://tabgroupsbtn/content/addon.jsm:104:7
watchWindows@chrome://tabgroupsbtn/content/addon.jsm:124:3
startup@resource://gre/modules/addons/XPIProvider.jsm -> jar:file:///home/.../.mozilla/firefox/....default/extensions/tabgroupsbtn@char101.github.com.xpi!/bootstrap.js:53:3
this.XPIProvider.callBootstrapMethod@resource://gre/modules/addons/XPIProvider.jsm:4662:9
this.XPIProvider.updateAddonDisabledState@resource://gre/modules/addons/XPIProvider.jsm:4789:13
this.XPIProvider.updateAddonAppDisabledStates@resource://gre/modules/addons/XPIProvider.jsm:4124:7
this.XPIProvider.observe@resource://gre/modules/addons/XPIProvider.jsm:4234:9
ModifyPref@chrome://global/content/config.js:611:5
ModifySelected@chrome://global/content/config.js:554:5
ondblclick@about:config:1:24

I can change the tab groups from the toolbar but it's not possible to to close the tab group neither using right click nor the menu buton. Might be related to upgrade of the Tab Groups extension (which replaces built in Firefox tab group support)

TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TypeError: this.previewFromTab(...) is undefined WindowsPreviewPerTab.jsm:537:9
TypeError: group is null ui.jsm:63:7
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TypeError: this.previewFromTab(...) is undefined WindowsPreviewPerTab.jsm:537:9
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TypeError: this.previewFromTab(...) is undefined WindowsPreviewPerTab.jsm:537:9
TypeError: group is null ui.jsm:63:7
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TypeError: this.previewFromTab(...) is undefined WindowsPreviewPerTab.jsm:537:9
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TypeError: this.previewFromTab(...) is undefined WindowsPreviewPerTab.jsm:537:9
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TelemetryStopwatch: requesting elapsed time for nonexisting stopwatch. Histogram: "FX_PAGE_LOAD_MS", key: "null" TelemetryStopwatch.jsm:297:0
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TypeError: this.previewFromTab(...) is undefined WindowsPreviewPerTab.jsm:537:9
TypeError: group is null ui.jsm:63:7
TypeError: group is null ui.jsm:63:7
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TelemetryStopwatch: requesting elapsed time for nonexisting stopwatch. Histogram: "FX_PAGE_LOAD_MS", key: "null" TelemetryStopwatch.jsm:297:0
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TypeError: this.previewFromTab(...) is undefined WindowsPreviewPerTab.jsm:537:9
TypeError: group is null ui.jsm:63:7
TypeError: aBrowser.adjustPriority is not a function NetworkPrioritizer.jsm:101:5
TypeError: this.previewFromTab(...) is undefined WindowsPreviewPerTab.jsm:537:9