That's great. Thanks for letting me know.

I see the problem in your own gallery but I have been unable to replicate it in a test gallery of my own using, reproducing your gallery as closely as possible (using the same configuration options that your gallery uses and using image captions with links).

The main difference between your own setup and mine is the web server the galleries are hosted on.
This problem may be related to server-side caching.
If caching is disabled on your web server, then Juicebox will have to download the images every time it needs them (as it will not be able to request them from a cache) and this may be causing the problem.
If you have an Apache web server and have a .htaccess file with an entry such as the following (to disable caching), then please try removing it to see if it helps.

Header set Cache-Control "max-age=0, private, no-cache, no-store, must-revalidate"

Otherwise, please check with your web host to see if caching is enabled on your hosting account (and if not, ask if they could enable it).

Be sure to clear your browser's cache after making any changes and before reloading your gallery's web page.

Hopefully this will help.

OK. They should certainly be able to point you in the right direction.

The problem might be finding the correct element(s) to apply a high enough z-index to.
However, once you find them, you might need to use a z-index value higher than 9999. (Juicebox uses z-index: 9999; for the #jb-glry-dlg container in the 'jbcore/classic/theme.css' file).
Whatever ids or classes you were setting the z-index to 9999 on, try using a higher value to see it this helps.
Otherwise, whatever plugin you are using to display your hidden images, try contacting their support and ask how to increase the z-index value. They should know which elements/classes within their script the z-index value should be applied to.

When a gallery is expanded (for example from the Splash Page on a mobile device), the gallery always fills the viewport.
It is not possible for a gallery to expand and retain features of the embedding page.
However, you can choose not to use the Splash Page and, instead, display the gallery directly in your web page (on the same page as your navigation menu where the Splash Page currently is) by setting showSplashPage="NEVER" (in JuiceboxBuilder-Pro's 'Customize -> Splash Page' section).
Alternatively, you could set screenMode="LARGE" ('Customize -> General') to force the gallery to be displayed in Large Screen Mode on all devices and in all browsers. Large Screen Mode does not use the Splash Page by default (unlike Small Screen Mode).
For more information on screen modes and how Juicebox adapts to different devices and screen sizes, please see here.

In order to avoid the possibility of galleries being overwritten, I recommend that you save each gallery to a different folder. This keeps all galleries separate from each other and helps to keep things organized.
If you like, you can create a new empty folder for each gallery (maybe on your desktop) before building your gallery with JuiceboxBuilder-Pro. Then, on the 'Publish' tab, navigate towards this folder (via the 'Browse...' button) before saving your gallery inside it.

If you have all your galleries saved into individual folders, you can then upload the complete gallery folders (not just the contents) to your web server and embed the galleries into your web pages using the baseUrl method documented here.

When you click 'Open Gallery' you then need to navigate towards the gallery folder that you want to open. Highlight the gallery folder (do not go inside it and select a file) and click 'Select Folder'.
If you do not get a pop up 'Select Gallery Folder...' window when you click 'Open Gallery', then close JuiceboxBuilder-Pro and delete the following folder manually before re-opening the application and trying again. This should hopefully help.
Mac: /Users/your_username/Library/Application Support/Adobe/AIR/ELS/JuiceboxBuilder-Pro
Windows: C:\Users\your_username\AppData\Roaming\Adobe\AIR\ELS\JuiceboxBuilder-Pro

I'm glad you've been able to solve your problem.
Thanks for letting me know.

You're welcome.

If you want to save a specific combination of settings, you will need to create a template.
With the settings as you want to save them, click the + sign to the right of the text 'Template Browser' (in the left panel of the 'Web' section) and select a name for your template.
At any time in the future, if you want to apply these settings, expand the 'Template Browser' control panel, scroll down to the 'User Templates' section and select your template.

If you want to save a specific combination of settings, you will need to create a template.
With the settings as you want to save them, click the + sign to the right of the text 'Template Browser' (in the left panel of the 'Web' section) and select a name for your template.
At any time in the future, if you want to apply these settings, expand the 'Template Browser' control panel, scroll down to the 'User Templates' section and select your template.

It looks like the white line you refer to is visible in desktop browsers, too.
There is a horizontal scroll bar on your web page and if you scroll to the right, you should see the white line.
It seems to be spanning the whole content of your page rather than just your gallery so I don't think the gallery is the root of the problem.

You could test this theory by reverting to whatever version you used before the update. I don't think it will help but it might eliminate (or point towards) Juicebox v1.4.4 being a possible cause.
Also, you could temporarily replace the gallery with just a plain empty <div> with the same dimensions that your gallery would have to see if the gallery has any effect or not.

Being that the white line is visible in desktop browsers, it might be a little easier to troubleshoot using your browser's developer tools.

I notice that if you prevent the 'bootstrap.min.css' file from being loaded, the horizontal scrollbar goes away and the thick white line to the right of the content is spit evenly into two thin white lines to the left and right of the content.

I think the layout of your page is somehow the root of your problem but, unfortunately, there is a large amount of CSS on your page (in several external files) and pinpointing the exact cause of the problem might be difficult (although I'd start be searching through your CSS looking for margin and padding rules).
I hope this at least points you in the right direction.

With regard to the meta viewport tag, the version of the tag in our blog entry is required only for full-browser gallery pages (where the gallery has dimensions of 100% x 100% and is the only content on the page). As your gallery is embedded in your web page alongside other content, this tag is not required and you can just keep your existing tag.
As the long tag contains all the 'content' that your existing tag uses, you could just replace your existing tag with the long version (if you were to use it).

It is not possible to right-click and save an image in a Juicebox gallery but you can set showOpenButton="TRUE" (in JuiceboxBuilder-Pro's 'Customize -> Lite' section) to display the Open Image button in the gallery's Button Bar.
When the Open Image button is clicked, the current image will be opened in a new tab where the user can save the image via a right-click or the browser's file menu.
This is noted in this FAQ:
How do I allow or prevent users from saving gallery images?

The Open Image button can be seen in this demo gallery.