I did test the install after clearing the cache and also in a fresh Joomla installation. Anyway, I did test it again and have the same problem.
There is no need to share my backend since I tested it in a new Joomla installation, in fact I searched vData forum and found the same error in the toolbar in screenshots from many posts as long as June 2017, more than a year ago.
You can see for yourselve in the following threads.
The toolbar is different from the screenshot from vData product page as you can see in the following image.
If you fix the toolbar you probably fix the editor button since they use the same CSS rule. Anyway I'm just reporting the problem since I already fixed that in my website.
Please download/install the version again and please clear your browser cache and try again? If you still find some issues, Please share your backend & FTP login credentials via Contact us form, We'll look into it.
The first issue (Select Columns) was fixed with the latest update but the others were not fixed.
To find the text editor issue: in vData menu click in Data Display, then open Blog data display and go down to Insert Fields editor in the bottom the Joomla buttons Menu, Contact, Article, Image and Page Break have the issue.
Note: to see the buttons you need to have the plugins for each of these buttons enabled.
For the toolbar in the Data Display page just look at the buttons at the top. It's hard to see all the icons.
in vData 2.9.23 all the choices from Select Columns, Primary / Unique Key or any other choice the label is unreadable because of the background color of "body.com_vdata .chzn-container-multi .chzn-choices li.search-choice" that is set to #f6f6f6 in the adminstyle.css (see Select-columns.png attachment).
There is a another CSS problem. This time is in the editor-xtd-buttons because of the 'color: #fff;' of the ".btn-toolbar .btn". It also happens in the btn-toolbar because of the same style, so if you have another Joomla extension for example Regular Labs Cache Cleaner in the same toolbar you can't see the label because your extension css overrides the backend template (see editor-xtd-buttons.png and toolbar.png attachments).
I tested in a fresh Joomla 3.8.10 install to make sure and the problem is the same in Chrome and Firefox.