i use Contentblocks for many of my websites. with the last Update form Contentblocks 1.11.1-pl, and TinyMCE Rich Text Editor 2.0.1-pl.
In one case, i got an Setting in a Content-Blocks Field. On click on the gear icon in content-blocks element i got a rich-textwindow in a modal. all fine. at the last update from tiny mce the window for an hyperlink is under the tiny-mce itself. the editors cant see it. afer close the tiny-mce you can see it, but you cant save it
it is possible to change the z-index, or a other fway to fix it