jktgeorge, скачай 
отсюда последний билд, в нём это должно быть подправлено. По крайней мере drug-n-drop на кнопку стал рабочим, плюс много других доработок: [more=ChangeLog]2015-06-24  Moritz Bunkus  <moritz@bunkus.org>   
         * MKVToolNix GUI: merge tool bug fix: if »automatically set the 
         file title« is enabled then the title field will be cleared after 
         all source files have been removed.   
         * MKVToolNix GUI: new watch jobs tool feature: the first tab 
         showing the output of the current job has been changed to show the 
         output of all jobs that have been run since the GUI's been 
         started. This can be turned off in the preferences so that only 
         the output of the currently running job is shown 
         again. Implements #1263.   
         * MKVToolNix GUI: merge tool bug fix: fixed a crash when 
         enabling/disabling chapters coming from an appended file. Fixes 
         #1293.   
         * MKVToolNix GUI: new merge tool feature: added an option to set a 
         directory relative to the first input file as the default output 
         directory. Implements #1261.   
         * MKVToolNix GUI: merge tool bug fix: it was possible to set the 
         »default track flag« to »yes« for multiple tracks of the same 
         type. Fixes #1289.   
         * MKVToolNix GUI: enhancement: the »open file« dialogs for the 
         chapter and header editor tools will use the same directory that 
         was last used in the merge tool. Fixes #1290.   
 2015-06-23  Moritz Bunkus  <moritz@bunkus.org>   
         * MKVToolNix GUI: bug fix: fixed reading the »default track« flag 
         of tracks from added Matroska files. Fixes #1281.   
         * MKVToolNix GUI: new feature: added a check box to the 
         track/chapters/tags/attachments list. This offers an additional 
         way of toggling the »mux this« state of entries, same as the drop 
         down box on the right and as double-clicking on the 
         item already did. Implements #1277.   
         * MKVToolNix GUI: merge tool bug fix: when appending files with 
         multiple tracks of a type (e.g. multiple audio tracks) then all 
         tracks of that kind would get assigned to the first track of that 
         kind of the file they're appended to. Now the second audio track 
         from the appended file is appended to the second audio track of 
         the existing file, the third to the third etc. Fixes #1257.   
         * MKVToolNix GUI: merge tool bug fix: fixed automatic output file 
         name re-generation when the mux status of tracks changes. Fixes 
         #1253.   
         * MKVToolNix GUI: new feature: added an option for always using 
         the suggested description and not asking the user when adding a 
         job to the queue. Implements #1288.   
         * MKVToolNix GUI: job queue enhancement: added the shortcut Ctrl+R 
         for the menu entry »start all pending jobs«. Implements #1287.   
         * MKVToolNix GUI: new feature: added an option to always treat 
         files dragged & dropped external applications as being added 
         circumventing the question what to do with them (add, append or 
         add as additional parts). This option is enabled by default 
         changing the default behavior from release 8.0.0. Implements 
         #1259.   
         * MKVToolNix GUI: new feature: added an optional action after 
         starting a job or adding one to the queue. This can be either to 
         create whole new settings or to only remove all input 
         files. Implements #1254.   
         * mmg: bug fix: the deprecation warning will only be shown 
         once. Fixes #1252.   
         * Installer for Windows: enhancement: associated the .mtxcfg files 
         with MKVToolNix GUI. Implements #1258.   
         * MIME and desktop files: enhancement: added file associations for 
         .mtxcfg with MKVToolNix GUI. Implements #1258.   
 2015-06-22  Moritz Bunkus  <moritz@bunkus.org>   
         * MKVToolNix GUI: new feature: implemented command line 
         handling. You can open configuration files, add files to merge 
         jobs, open files in the chapter or header editors. Implements 
         #1209.   
 2015-06-21  Moritz Bunkus  <moritz@bunkus.org>   
         * mkvmerge: bug fix: fixed recognition of (E)AC3 audio tracks 
         using a FourCC of »ec-3«. Fixes #1272.   
         * MKVToolNix GUI: merge tool bug fix: fixed attachments not being 
         merged into the file in certain situations. Fixes #1260.   
         * MKVToolNix GUI: merge tool bug fix: fixed showing existing 
         attachments present in source files in the »tracks, chapters, tags 
         and attachments« list. Fixes #1256.   
         * MKVToolNix GUI: merge tool bug fix: the jobs created when 
         appending files were incorrect resulting in an error message from 
         mkvmerge. Fixes #1271.   
         * mkvpropedit: bug fix: fixed a warning about »edit specifications 
         resolving to the same track« when changing the track properties 
         and setting tags for the same track simultaneously. Fixes #1247.   
         * MKVToolNix GUI: merge tool bug fix: the output/destination file 
         name is cleared when all files are removed. Fixes #1265.   
         * MKVToolNix GUI: merge tool bug fix: fixed command line escaping 
         for empty arguments. Fixes #1270.   
         * MKVToolNix GUI: merge tool bug fix: fixed creating files without 
         a title if one of the input files contains a file title. Fixes 
         #1264.   
         * MKVToolNix GUI: bug fix: if the job removal policy is set to 
         »remove even if there were warnings« then jobs that were muxed 
         without warnings weren't removed. Fixes #1262.   
 2015-06-20  Moritz Bunkus  <moritz@bunkus.org>   
         * Build system: fixed inclusion of desktop files for the two GUIs 
         for Debian/Ubuntu packages. Fixes #1255.[/more]