<script>
tinymce.init({
//省略
toolbar_location : "bottom",
});
</script>
これこれ。結構探した。
https://github.com/tinymce/tinymce/issues/4618#issuecomment-586529196
TinyMCE 5.2.0 was released to the community earlier this week, which added a new toolbar_location setting that can be used to set where the toolbar should be rendered. The valid values are 'top' (default) or 'bottom'. Here's a fiddle to show how to use the new setting/feature: http://fiddle.tinymce.com/8bhaab/1. There is one issue we're aware of with the new feature when opening an inline dialog (eg search and replace) when sticky toolbars is also enabled. We'll include a fix for that in a future release. Please let us know if you have any further issues.
