This versions contains UI improvements requested by users and many fixes.

Changes:
* Added Popup menu for whole toolbar with options to Show/Hide Security Scan and Driver Scan button
* Settings related to tray moved from the Options to the Tray Icon and the Tray Hint Settings
* Removed 0 days/0 hours from Uptime/Idletime
* Improved Tray Hint information positioning
* Translations Updated
- Fixed neverending start of System Explorer with enabled "Require Administration"
- Fixed submenus in new style menu
- Fixed Tray Hint Battery status for computers without Battery
- Fixed issues with installation/uninstallation of service
- Next minor fixes

+ (rc1) Toolbars: store toolbar assignments in screensets

+ Actions: toggle multichannel track metering, now in track menu
+ API: added SetProjectMarker3() and AddProjectMarker2() for setting custom marker colors
+ API: threading fixes for GetSetObjectState() and other related APIs
+ Directory cleanup: now looks for media references in project bay media items
+ Envelopes: fixed editing point values for FX wet/dry envelopes
+ Envelopes: pitch envelopes snap configuration (1 semitone, 50 cent, 25 cent, 10 cent, 5 cent, 1 cent, off)
+ Fades/crossfades: prevent unintentional crossfade edits when media items are adjacent but not crossfaded
+ FX: fixed possible excess midi notes on loop when PDC FX are used
+ FX: improved undo state tracking when copying/moving FX between tracks
+ FX: if project samplerate set and loading project, try to initialize loaded plug-ins at correct rate (avoid later reinit)
+ FX: pin mappings are now stored more safely, fix for possible race conditions
+ Freeze: actions to render tracks in-place with FX, then save/remove existing media and online FX
+ Freeze: menu actions in FX chain window to freeze track up to last selected FX
+ Grouping: fix for rare item group reuse bug
+ Media explorer: fixed crash issue when group policy prevented embedded explorer (falls back to non-explorer view)
+ Metering: new multichannel tracks default to multichannel metering enabled
+ Metering: master multichannel metering is now optional
+ Mixer: scroll improvements/fixes
+ Mixer: opening/unhiding mixer now makes last selected track visible
+ MIDI: use MIDI track name event when importing files
+ MIDI files: options to automatically snap time signature changes, tempo changes on file import
+ MIDI editor: switching sources via filter window no longer unhides all other sources
+ MIDI editor: undo fixes, especially related to list editor
+ MIDI editor: note properties fixed reset of combo boxes on multiple note selection
+ MIDI editor: inline editor marquee fix
+ MIDI editor: fixed bug when quantizing notes that were drawn in (not painted or recorded)
+ MIDI editor: fixed context menu doubleness when clicking above piano keys
+ Mouse modifiers: support ripple edit (off, one track, all tracks) while moving items
+ Mouse modifiers: import/export mouse modifier support (.ReaperMouseMap files)
+ OSX: better behavior when using modal windows (such as save as with convert) when REAPER inactive
+ Playback: corrected minor rounding bug on playback start in certain instances
+ Relative snap: avoid clearing snap offset when copying media items
+ Render: new user setting for tail length to use in project render, stem render, track freeze
+ Render: fixed certain issues with filename wildcards
+ Scale finder: button to use selected notes in MIDI editor
+ Sends: shift+drag IO from unselected track to selected uses all selected tracks as receivers
+ SRC: fixed quality/synchronization issue (4.0x regression)
+ Toolbars: store toolbar assignments in screensets
+ Topmost pin buttons: bug fixes, buttons now remember their last states (based on window title)
+ Track manager, region manager, project bay: columns can be reordered
+ Track manager: added freeze column/button
+ Vertical zooming: scrollbar fixes, better behavior
+ Video: improved rendering accuracy, support for rendering with playrates
+ Video/FFmpeg: updated API to support the newest FFmpeg/libav version (v53)
+ VST: support effSetSpeakerArrangement notifications for plug-ins