Shortcut to show/hide the color panel (like Tab shows Timeline)

[fccfc5d245c]

Is your feature request related to a problem? Please describe

• I mix or pick palette colors very often, so I need to access the left panel (I'll call it color pane) constantly
• I can't do that on Advanced Mode, so I have to press the keys fn+F11 two times in order to get out of Advanced Mode, make or pick my color, then fn+F11 again to get the valuable screen real state back
• It becomes frustrating really fast, considering how easy it is to bring out the Timeline pane with Tab

Describe the solution you'd like

Tab works like a charm for showing/hiding the Timeline, so we could have another user defined shortcut to toggle the color pane

Describe alternatives you've considered

• F4 shows the Palette Editor, but it's very difficult to see the color you're getting without the visual aid of the color pane
• Configuring my keyboard to avoid the need to press fn, but that doesn't make it much easier and, also, I use my multimedia keys more
• Working only in the not advanced mode, which is the best option for tweaking colors often, but the screen dedicated to the actual painting is too small
• Lowering the Screen Scaling, but every button becomes too tiny

Additional context

But hey, I love LibreSprite, thank you for coding it and long live FOSS and pixel art!