I've just started going through things & this is the obvious Alt+? actions that I've found from the plug-ins & trying out a few of the skins to see what was being generically used. There's still the chance I've missed something & that other combinations of skins &/or plug-ins are already making use of them.
A - Album Art Window
B -
C - Skin Settings
D - Colour Themes
E - Playlist Editor Window
F - Modern Skin File Menu (not a window thing)
G - Equaliser Window / Embedded tab toggle
H - Modern Skin Help Menu (not a window thing)
I - Modern Skin View Menu (not a window thing)
J -
K - Open configuration for current Visualisation plug-in
L - Media Library Window
M - Minimise
N - Modern Skin Show/Hide Browser tab/view ?
O - Modern Skin Options Menu (not a window thing)
P - Modern Skin Play Menu (not a window thing)
Q - Queue Manager Window
R -
S - Skin Options
T - Insert separator
U -
V - Video Window
W - Main Window / Main UI depending on skin
X - Modern Skin Show/Hide Browser tab/view ?
Y - Lyrics Window
Z - Undo playlist changes
So from that, I can probably use
Alt+B for Big Clock (which makes sense), for Waveform Seeker using
Alt+R is probably the more sensible one to use so it matches up to part of what's in the string. Otherwise it's then going into using numbers (not Alt+3 as that's already taken) or punctuation characters if there's a desire to support even more windows (ignoring that modern skins can self-register them too).
I'm not going to implement the thing suggested in my reply above for now as I've too much that already needs to be finished off to get a new preview build out the door.
-dro