bug(compatibility): gemini-scrollbar + FancyBox

[Kristinita]

At first, I post this issue for FancyBox issue tracker, but FancyBox owner closed issue without solve.

1. Summary

I click to image → make some actions in FancyBox menu (run slideshow for example):

    page scroll to top.

I have this behavior for Gemini scrollbar and no reproduce for native browser scrollbars.

I don't reproduce a bug for browsers native scrollbar.

2. Environment

2.1. Scripts

• JQuery 3.3.1
• FancyBox 3.5.6
• Gemini Scrollbar 1.5.3
• JQuery Lazy 1.7.10

2.2. Tested browsers

I reproduce the problems in browsers versions without addons and users settings:

• Firefox 65.0 (64-bit)
• Chrome 71.0.3578.98 (Official Build) (64-bit)

2.3. Screencast writing

• ScreenToGIF 2.16
• LiceCAP 1.28
• ActivePresenter Free 7.5.4

I post this information, because I have strange behavior.

If I record GIF:

    problem not reproduced. I can record GIF from about tenth attempt.

Else:

    problem reproduced quickly, almost immediately after the start of the FancyBox slideshow.

3. MCVE

(Yes, it minimal example)

• Repl.it sources
• Repl.it demo
• GIF (GitHub for some reasons don't support 5,19 Mb GIF)

4. Steps to reproduce

I open my demo page → I scroll page to any image → I run FancyBox slideshow.

5. Expected behavior

If default scrollbar:

    no scrolling to top of page.

See examples here and here.

6. Non-expected behavior

Else Gemini scrollbar:

    scrolling to page top. See GIF from MCVE for example.

7. Not helped

I read many similar questions → try solutions from answers and comments → no effect.

1. $.fancybox.defaults.hideScrollbar = false; as @fancyapps say

2. $.fancybox.defaults.autoFocus = false; as @fancyapps say

3. Dave Kiss most popular Stack Overflow answer

4. @sohel-ahmed-ansari variant

5. @theexpand and @hsobhy variants

6. @Joeran answer. I try modified it to Gemini methods → also no effect.

   $('.KiraNotLazy').fancybox({
    beforeLoad: function(){
     internals.scrollbar.destroy();
       },
    afterClose: function(){
      internals.scrollbar.update();
     }
   });

Thanks.