No Flash plugin reported although installed on computer
Other than previous versions of Opera (I have 35.0.2066.68) the Flash plugin does not show up in the Opera-plugin-list and therefor cannot be enabled. Websites detect the flash plugin as missing and request installing. But Flash is installed on the PC and is used by Internet Explorer without problems.
Can this issue have something to do with flashblock-plugin? However, previous versions of Opera had no problems with both flash plugin and flashblock.
There are currently 3 Flash plug-in variants in existence, each of which works with different browsers. As @leocg notes, the ppapi version works with Chrome-based browsers like the current Opera; the active-x (or 'aex') version works with IE; and the npapi version works with Firefox and Olde Opera. And yes, you can (and may need to) have all versions successfully installed on the same computer - I do. When Flash updates its version number, you may need to update each variant separately (unless one or any are set to auto-update).