Hello.

In version 14.0.1.1965 (and in previous builds also) when I trying to open CLOB result of the "dbms_sqltune.report_sql_monitor" with type => 'ACTIVE' or 'HTML', Pl/SQL Developer suggesting me to open it in "Google Chrome".
When I press "Yes" or "No", a result always opening by internal viewer of PL/SQL Developer.
If in opened subwindow with CLOB-result I'm navigating into the rightest tab - "External" - and specifing "<...>\chrome.exe" and press "Execute", then Chrome getting the result and showing result as expected.
So, there is some problem with default calling Browser and passing a result to it.

In the PL/SQL Developer 13 that was working great.

Can you go to Configure > Preferences > User Interface / Options, press the "DSA Dialogs" button and check if there are lines with "Edit.xml" and "View.xml"? If so, can you delete them and try again?

There is no such lines.
There is 2 commented lines and then a couple of "ExceprtiobAt$..."
and one "AutomaticStatistincsDisabled=1"

Okay. We'll investigate this.