I’ve had this problem several times now, but it’s only today that I’ve decided to report it. Basically, when I do my lesson session and sort of wander away to do some other stuff for some time (because I can’t concentrate much), when I return, the session kinda gets “stuck”, so I can’t advance to the next item or return to the previous one, the arrow buttons on the sides and the item buttons below do nothing (the arrow buttons actually only work on the current item, but do nothing when it’s supposed to go to the next tiem), or rather they give an error in JavaScript console.
It may be the userscript that causes it, but I’m not sure.
Errors as a text:
userscript.html?id=9e767782-210e-459f-904b-fa83978e98bc:424 Uncaught TypeError: Cannot read property ‘concat’ of null
at Array.toggler (userscript.html?id=9e767782-210e-459f-904b-fa83978e98bc:424)
at r (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:58)
at c (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:58)
2application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96 Uncaught TypeError: Cannot read property ‘2’ of null
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at HTMLLIElement.dispatch (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement.m.handle (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:25)
2application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96 Uncaught TypeError: Cannot read property ‘0’ of null
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at HTMLLIElement.dispatch (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement.m.handle (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:25)
application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96 Uncaught TypeError: Cannot read property ‘1’ of null
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at HTMLLIElement.dispatch (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement.m.handle (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:25)
at Object.trigger (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at Function.each (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:14)
at pe.fn.init.each (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:14)
at pe.fn.init.trigger (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at Object.prevItem (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at n (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96 Uncaught TypeError: Cannot read property ‘0’ of null
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at HTMLLIElement.dispatch (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement.m.handle (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:25)
at Object.trigger (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at Function.each (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:14)
at pe.fn.init.each (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:14)
at pe.fn.init.trigger (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at Object.prevItem (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at n (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96 Uncaught TypeError: Cannot read property ‘4’ of null
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at HTMLLIElement.dispatch (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement.m.handle (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:25)
at Object.trigger (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at Function.each (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:14)
at pe.fn.init.each (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:14)
at pe.fn.init.trigger (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at Object.prevItem (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at n (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
3application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96 Uncaught TypeError: Cannot read property ‘2’ of null
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at HTMLLIElement.dispatch (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement.m.handle (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:25)
(anonymous) @ application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96
dispatch @ application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26
m.handle @ application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:25
application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96 Uncaught TypeError: Cannot read property ‘1’ of null
at HTMLLIElement. (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:96)
at HTMLLIElement.dispatch (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:26)
at HTMLLIElement.m.handle (application-d3336a7fbfc736af2217ee5088f57ea0f9ce69e0764063606df527b3c61e9305.js:25)