Update 260201a
 Added 'WT_' to the name of the script, also to my skyscraper.
 Fix script failure when all tracks are deleted.

Update 260201b
 Fix crash when loading a project with a saved selected track state.

Update 260201c
 Fixed error in 260201b that broke mouse interactions.
 Fixed media track validation crash.

Update 260202
 Added functionality for dragging over the cable/socket of a master/parent send to toggle the track's master/parent send state. Enable it with the new preferences entry; disabled by default.

Update 260203
 If a cable runs off the top or the bottom of the screen, position the floating control in the middle of the visible bit.
 Clicking on a cable now summons the floating control, instead of waiting for a drag.
 Double clicking on a cable now resets its value to zero.

Update 260204
 Fixed media track validation crash.
 Fixed image errors for 150% horizontal (braided) and 150% vertical (hollow) cables.
 New preference 'Mousewheel adjusts the send level of a cable', enabled by default.
 
Update 260205
 Checks whether the user is running REAPER 7.53 or later, warns if not.
 Fixed receives to channel 3/4 from tracks above the selected track not being correctly styled.
 
Update 260207
 Added support for TCP pinned tracks.
 Rebuilt cable styling internal assignment and interaction in preferences (preparation for possible additional definitions).
 Added support for collapsed parents being fully hidden.
 Added brightness preference for sccript background colour.
 Fix HiDPI text padding.
 
Update 260209
 Script can now ask REAPER if the arrange window tracks have scrolled vertically, even when the script does not have focus. Added preference control for the rate at which to do this. 
 Bug fixes.
 
Update 260210
 Fix the visible envelope panels of pinned tracks not being included in the 'pinned area' behaviours.
 Fix crash due to sends to/from hidden but not folder-ed tracks.
 
Update 260211
 New cable styles : 'Faint' and 'Dashed'.
 Image for the socket of a selected track re-styled to better create the expectation that this will be the source of a cable.
 Fix track scoll detection breaking if the first visible track is pinned or hidden.
 
Update 260212
 Send and receive cables may now be styled differently if they are muted. Defaults to the new 'faint' cable style, colored red, custom color disabled, but you can fully assign all that in preferences. 
 
Update 260214
 Cables now do the Reaper behaviour of alt-click to delete, shift click to mute.
 Robustly prevent spurious appearances of the channel3/4 socket if the mouse rapidly moves away while the script is thinking about something else. 
 Border added to styling preferences to clarify what preferences the cable category buttons relate to, plus some other styling niceties.
 Script version added to bottom of the preferences page.
 Keep track of the send/receive mute status in Reaper and update cables if it changes.

Update 260217
 Unified cable colouring preferences. Six preset colours to choose from, and six slots that remember the most recent colours you chose yourself with the colour picker.
 Added tooltips to toolbar buttons, added preference for tooltip delay to settings page, defaults to 0.8 seconds.
 
Update 260219
 Can now also create 'MIDI only' sends, drag and hold over a destination socket to see the MIDI socket.
 New cable types: Send (MIDI only) and Receive (MIDI only). Both default to the recently new 'dashed' line style.
 Number keys no longer show dev buffer debugging views.

Update 260221
 Script toolbar now matches the height of Reaper's toolbar. 
 Fixed pinned track and envelope cuttoff calculations for HiDPI OSX