"Hidden" features:

v1.2
[File info] Right click on Path to open in explorer
Switch tabs button (Nothing > Icons > Icons & Text) reverts on Right click

Previous:
Double Click on Songticker opens Edit tag dialog
Right-Click on Songticker for a useful menu
Right-Click on pause button to restart playing track
Right-Click volume icon to quickly mute-unmute
Right-Click on Main menu button opens Winamp Preferences
Ctrl. + F will perform a web search of what's curently playing (EXCEPT IF Playlist is opened)
Winamp Bolt logo is a "Multi-button": Right-Click to choose its functionality
[Multi-Button Bolt] If set to "Change Color Theme", Ctrl. + Click will switch to previous CT instead of next.
Bigger Visualizer windows have a custom button, specially handy to access your presets folder
[File info] Click on Title / Artist / Album to do a web search about it
[File info] Hovering your mouse over the album art will show a button to hide it
[Playlist editor] Click over the Time area for an extra menu
[Playlist editor] When in the search box, hit Escape to close it
[Playlist editor] Right-Click on Search box for a history of your searches
[Side-Playlist editor] Right-Click on Collapse button will show the Album art window
[Album art ] Double Click will get you to the currently playing item's folder
[Album art ] Right-Click has many options (even on streams!)
[Multi-tools] A colored ring around the button means you have set a specific function for it (other than the default one)
[Web Reader] Right-Click on the Title bar will open and external browser / web browser.
[Shade mode] Right-Click on Switch button works as minimize
F11 toggles Fullscreen (just like in Explorer)
Click on Shade mode Songticker brings up a Quick Playlist (can be disabled from Skin settings).