Hi, I'm the developer of the PDF Translate add-on.

Some add-on users report an error of right sidebar loading failure. I found it's caused by a strange behavior of js script. Here are two functions of my add-on:

getReader: function () {
return Zotero.Reader.getByTabID(Zotero_Tabs.selectedID);
},
getReaderID: function () {
for (let i = 0; i < Zotero.Reader._readers.length; i++) {
if (Zotero.Reader._readers[i].tabID === Zotero_Tabs.selectedID) {
return i;
}
}
},

They work fine, while in very accident case they behave strange. Some tests in the Run JavaScript Window when these behavior happens:

1. call getReader. the function definition is shown correctly.
2. call getReader(). return undefined(should return a reader object)
3. call Zotero.Reader.getByTabID(Zotero_Tabs.selectedID). return an valid reader object.
4. getReader = function(){return Zotero.Reader.getByTabID(Zotero_Tabs.selectedID);}, then call getReader(). return an valid reader object.

5. call getReaderID. the function definition is shown correctly.
6. call getReaderID(). return undefined(should return a reader index)
7. call the for loop directly. return a valid reader index 1.

8. call Zotero_Tabs.selectedID. return a valid tab id 'tab-Xt9g83mm'

The debug ID is 1978557902.

I think this may be caused by some inside bug of Zotero tabs/reader. Could you please help?

Thanks very much!