Sure will have solution. The faster way is Don't enable bootstrap in admin mode since that's the problem.
I have not check the theme, but there will be a add_to_head(); which themes usually would do, the method will be used to call bootstrap .js and .css files. And it usually will be made in the first few lines in theme.php (all coders do this usually)... Again I am just guessing here.
While it is on front end, yes responsive and everything because you can theme side and table and layout the render page grid. But not in Admin Panel since the add news page has a problem.
Now, you gotta mod that theme via this method... To stop loading bootstrap when admin panel is on.
if (!ADMIN_PANEL) { ... Add bootstrap header inside here }
Next method would be just recode the admin panel, or mod on the bootstrap CSS file with an extra .block file since bootstrap is base on float left (hence responsive).
So what I would do is to destroy the float via this.
if (ADMIN_PANEL) {
add_to_head("
<style>
div { display: inline-block !important; position:relative !important; float:none !important;}
</style>
");
}
Or something along with that nature (to destroy bootstrap CSS files) so it goes back to normal (I.e. Not responsive) on Admin panel.
Just a thought ..