Have narrowed down the CSS conflict for you to contact your template developer with. Within your template the issue is the following.
IN: /templates/shaper_helix3/css/template.css
Code:
.off-canvas-menu-init {
overflow-x: hidden;
position: relative;
}
That is currently being applied to the body element of the page. Unsure if that's being done in the templates index.php file it self or some sort of JS doing it. Removing this class from the body element was enough to prevent it from being a problem as there maybe other CSS being applied by that class that I didn't see.
IN: /templates/shaper_helix3/css/custom.css
Code:
.qtip-modal.qtip-fixed {
max-height: 25%;
}
The above is custom CSS you've added to your template. You're forcing the modal window to be no larger than 25%. Removing both of the above offending CSS completely resolves the problem. You can try using the below to force override both issues if you are unable to fix them.
Code:
body.off-canvas-menu-init {
position: initial;
}
.qtip.qtip-modal.qtip-fixed {
max-height: none;
}
Add the above to CBs template CSS override usage shown below.
www.joomlapolis.com/blog/kyle/18711-template-css-overrides-made-easy