This bug has been copied from bug #1632904 and has been proposed to be backported to 7.6 z-stream (EUS).
While testing over VNC on RHEL7.6.z and gnome-settings-daemon-3.28.1-3.el7_6, I do not see this issue fixed and it introduced other problems. The OSK doesn't pop up when you try using it in apps like gedit, terminal etc. There is another issue I cannot reproduce all the time but with the OSK enabled, I am unable to type using the physical keyboard into gedit or terminal. It spits out gibberish in the terminal and nothing in gedit, I will attach a pic.
Upon more testing, this issue is only happening over VNC and not locally to the machine. Will file new bug.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.