iframe width / height problem

hi,
i use the free version, and I have problem when I click on a thumbnail, the iframe open but its size is 300x150px . but its container has the good size ie: <div id=”vcboxLoadedContent” style=”width: 800px; overflow: hidden; height: 450px;”>
I dont understand why.
if I edit iframe’sstylemanually, then it is ok ie : style=”width: 100%; height: 100%;”
I cant show this bug because Im still in development phase, and only in my computer. I can do a printscreen if you want
thanks

https://ww.wp.xz.cn/plugins/gallery-video/