Runz windows can not be shown on firefox interface

[simplesafe]

Hi, Thanks so much for your great job! Runz is really of great assitance to me.

I found an issue that: when I opened a firefox window (on the top of desktop) and proceeded to open runz by pressing “#+j”， Runz windows does not appear as normal, after I minimized the firfox window, Runz restored working and appeared. When I works on either Chrome or IE interface, Runz window appears perfect without any problem.
Could you figure out the reason and solution?

PS: Windows 10 / Firefox Quantum 59.0.2 (X64)

[mocihan]

I installed Firefox Quantum 59.0.2 (X64), but it seeems working well.