We've made the overflow button visible in customize mode, but now its panel shows up when dragging items on top of it (despite the button being marked disabled, and the panel empty because its contents are in customize mode). The drag handlers should either be removed in customize mode and then readded, or (probably simpler) check whether the button is disabled before doing anything. Happily, this doesn't happen with the photon pref disabled.

Comment on attachment 8880391 [details] Bug 1371236 - don't try to open the overflow panel when in customize mode, https://reviewboard.mozilla.org/r/151760/#review156734 ::: browser/components/customizableui/CustomizableUI.jsm:4183 (Diff revision 1) > - let overflowableToolbarInstance = this; > - this._panel.addEventListener("popupshown", function(aEvent) { > - this.addEventListener("dragover", overflowableToolbarInstance); > + this._panel.addEventListener("popupshown", (aEvent) => { > + this._panel.addEventListener("dragover", this); > + this._panel.addEventListener("dragend", this); > - this.addEventListener("dragend", overflowableToolbarInstance); Not strictly necessary, but I noticed this and thought I might as well tidy it up a bit.

Comment on attachment 8880391 [details] Bug 1371236 - don't try to open the overflow panel when in customize mode, https://reviewboard.mozilla.org/r/151760/#review157308 Cool, nice and simple. Thanks for the drive-by cleanup. ::: browser/components/customizableui/CustomizableUI.jsm:4183 (Diff revision 1) > // case the edit controls are in it. > this._panel.addEventListener("popupshowing", () => doc.defaultView.updateEditUIVisibility(), {once: true}); > this._panel.openPopup(anchor || this._chevron); > this._chevron.open = true; > > - let overflowableToolbarInstance = this; > + this._panel.addEventListener("popupshown", (aEvent) => { nit, drop the parens on aEvent

Pushed by gijskruitbosch@gmail.com: https://hg.mozilla.org/integration/autoland/rev/5af23c6f9303 don't try to open the overflow panel when in customize mode, r=jaws

I have reproduced this bug with nightly 55.0a1 (2017-06-08) on ubuntu 16.04(64 Bit). The bug's fix is now verified on Latest Nightly 56.0a1 . Build ID 20170627100221 User Agent Mozilla/5.0 (X11; Linux x86_64; rv:56.0) Gecko/20100101 Firefox/56.0

I have reproduce this bug with Nightly 55.0a1 (2017-06-08)) on Windows 8.1 (64 Bit). This bug's fix is verified on Latest Nightly 56.0a1. Build ID : 20170627030209 User Agent : Mozilla/5.0 (Windows NT 6.3; WOW64; rv:56.0) Gecko/20100101 Firefox/56.0 [bugday-20170628]

As per Comment 7 and Comment 8, I am marking this bug as verified fixed.