I come to you to give you some explanations about my problem that seemed to come exclusively from alora theme. When in doubt I conducted several tests this morning. So I deactivated all plugins of the site and the theme alora.
Then I reactivated at a first a theme and plugin Theme4Press core and slider revolution.
GOOD NEWS your modification works perfectly.
In fact, there is another plugin (Caretta Weather Shortcode) which also adds a button to the TinyMCE editor that created this problem.
I again thank you for the speed and you have to listen to our problems.