I see what you mean. Curious it only happens with large blocks of text. You should be able to avoid the behavior by using G’berg’s code editor or the classic editor. I don’t think there’s much us end users can do to disable the behavior in G’berg. What you can do is post a new issue at Project Gutenberg’s GitHub site (free registration required). Please do a search first to be sure someone hasn’t already posted a similar issue.
By bottom bar, do you mean where it tells us where we are within a page’s block structure? For example:
Page > Row > Image
It can be disabled through (3 dot icon) general preferences, switch off “show block breadcrumbs”.
The only time there should be an up-extendable line is when there are additional meta boxes below the editor. Custom fields is a common one, but themes and plugins could add others. You should be able to turn off any meta boxes below the editor, or drag them over to the settings sidebar. Or use the distraction free view. Then the up-extendable line should disappear.
If all else fails, it could be hidden with some custom admin CSS, for example:
.edit-post-meta-boxes-main {
display: none !important;
}
This actually hides the entire main meta box area below the editor, not just the line. Adding admin CSS requires some custom coding. There might be a plugin that makes this easier, IDK.
