12.16 23rd July, 2019
The following changes were part of the 12.15.1 - 12.15.4 beta 
updates:
  - The Go, Recent and Favorite 
  commands have new NEWTAB=findinactive modes, similar 
  to NEWTAB=findexisting except that they will open a new tab 
  if the current tab already has the specified path. Intended for buttons which 
  reduce clutter by switching to existing tabs while retaining the ability to 
  open a second tab for the same folder when needed.
  
   - {dlgopen} and similar now allow you to use forward 
  slashes when specifying the initial path. (Automatically converted to 
  backslashes before calling the Windows API.)
  
   - Changes related to Lister Styles which specify Folder Tab 
  Groups:
  
  
    - The Close existing folder tabs checkboxes within Styles 
    are now used exclusively when applying a style. The similar checkbox within 
    Folder Tab Groups still works when loading a tab group on its own, but not 
    when loading one via a Style. This is the main change which may affect 
    existing configs.
  
     - Styles which explicitly specify File Display: Single, but also 
    specify a Tab Group which has tabs on both sides will no longer switch to a 
    dual-display Lister; right-hand tabs will be ignored.
  
     - When a Tab Group is specified, the options under it (View Mode, 
    Format, etc.) which are disabled in the UI are now also ignored 
    when applying the Style. Previously, they would still be applied.
     - If a Style specified a dual-side Tab Group in the UI for the left side 
    (which loads folders into both left and right), and nothing at all in the UI 
    for the right side, applying the Style would first load the default folder 
    into the right side, before loading the Tab Group over or in addition to 
    it.
 
   - If Explorer Replacement is configured to open into a new, dual-display 
  Lister, the left hand display which the double-clicked path is loaded into 
  will now always be given focus, regardless of how the default Lister was set 
  up.
  
   - Go TABCLOSE now works with the TABPOS 
  argument. While you could specify a tab index using the PATH 
  argument before, this change allows things like closing the next tab 
  (Go TABCLOSE TABPOS=+1) or previous tab (Go TABCLOSE 
  TABPOS=-1) relative to the current tab.
   - Fixed HTML codes appearing in progress window when connecting to FTP sites 
  in some situations (e.g. batch rename).
  
   - You can now scroll the Rename dialog's preview list with the mouse wheel 
  while editing the New Name field in macro mode.
  
   - The "Slide-out parent buttons" option was broken in beta 12.14.1, now 
  restored.
  
   - Clicking the full-screen button in the viewer pane when it was displaying 
  a non-image file (e.g. a PDF) would open the standalone viewer but not show 
  the PDF - instead, the first image file in the folder would be 
  shown.
  
   - For FTP servers that don't support MLST, file dates that are returned 
  without a year are now assumed to be the previous year if they are the current 
  month but a day in the future. E.g. if the current date is Jun-17-2019, and 
  the ftp site returns "Jun 30" as the date, that will now be taken as 
  "Jun-30-2018" and not "Jun-30-2019".
  
   - Made improvements to MTP code which will hopefully prevent 
  freezing/lockups with some devices (iPhones etc).
  
   - In Customize mode, dragging special folders like Recycle Bin to a 
  toolbar now creates better buttons for them. (Go PATH=/trash 
  instead of a cryptic IDL string.)
  
   - File paths copied to the clipboard when on MTP devices are now stripped of 
  the "?s1234?|"-style information at the end of path components which Opus uses 
  internally.
  
   - Fix for "Changing folders while Description is being calculated" ( https://resource.dopus.com/t/changing-folders-while-description-is-being-calculated/32742 
  )
  
   - Fix for double-clicking ".." parent item not working when the parent is 
  the Quick Access folder.
  
   - Improved consistency in how the Quick Access folder behaves 
  between navigations made via the folder tree, file display and Go 
  FOLDERCONTENT menus. In all cases, going to a folder below Quick 
  Access now positions you under Quick Access in the tree and 
  breadcrumb path field, such that parenting up will take you to the Quick 
  Access folder. (If you instead go down from there, you'll jump to the 
  folder's real location.)
  
   - Opus no longer tries to send offline files from OneDrive to the recycle 
  bin when deleting; if any offline files are selected the recycle bin will be 
  automatically bypassed. This prevents the files having to be downloaded before 
  being deleted with OneDrive in Windows 10 1903.
  
   - Fixed problems with MTP devices opening in Explorer in some 
  cases.
  
   - Fix for double-clicking some virtual folders under Quick Access taking you 
  to their normal locations instead of staying under Quick Access. e.g. Recycle 
  Bin, Dropbox and Creative Cloud Files.
  
   - Deleting junctions on network drives no longer deletes their 
  contents.
  
   - The Synchronize summary dialog now scales its column sizes for high 
  DPI.
  
   - When in a folder under Quick Access, the path field and parent buttons now 
  behave as if you are in the real folder.
  
   - Addressed a situation where the Jobs Bar Arrow appearing could place a 
  background Lister on top of the active Lister if a new progress dialog 
  appeared in a Lister which didn't currently have focus.