Using BACKSPACE for Edit Tool in Firefox on Windows not always working properly

[nasedil]

Somehow edit tools, for example BoxEditTool, do not work properly in Firefox on Windows: when trying to remove a box using BACKSPACE key after selecting it, Firefox instead goes back in history. Even when cursor is in the plot. That does not happen in Firefox on Linux.

ALL software version info (bokeh, python, notebook, OS, browser, any other relevant packages)

OS: Windows 10, version 18.09
Browser: Firefox 66.0.2

Description of expected behavior and the observed behavior

I loaded the https://bokeh.pydata.org/en/latest/docs/user_guide/tools.html page and then clicked on the 'Edit Tolls' shortcut ( https://bokeh.pydata.org/en/latest/docs/user_guide/tools.html#userguide-tools-edit ), scrolled down to the BoxEditTool integrated example. Then, I selected one of the boxes, and pressed BACKSPACE. I expected the box to be removed, but instead the top of the page was shown.

Screenshots or screencasts of the bug in action

[bryevdv]

I'll mark as bug but the reality is until some experienced windows users decided to help out with Bokeh, I don't know when this might get looked out.

[mattpap]

Maybe I can get this reproduced and fixed at PyCon.DE sprints.