I see that Screwtapello explained about showing and hiding widgets so I'll try to take the outline question.
I'm going throw a couple little pieces of information out there, hopefully it will all make sense.
The first is since you're doing art stuff I recommend turning the toolbars on if you haven't yet with [Decker > Toolbars]. They're really useful.
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The second thing is that there are two kinds of white in Decker. One is a solid opaque white, which is always treated as solid white in every circumstance.
The other one is a sometimes-transparent white that you can tell Decker to treat that white as 'clear' by turning on transparency in the Style menu or setting a widget to 'show: transparent'.
You can see the difference between them with a setting called Transparency Mask which makes that transparent white appear to be a different color (if you haven't modified the default Decker palette it'll become a neutral gray, if you have modified your colors then it'll be whatever happens to be in pattern slot 45). You can make this difference visible (only to you, it doesn't change anything in the project) with [View > Transparency Mask] or 'R' on your keyboard.
Here's an example of both transparency and transparency mask.
So there are two kinds of white:
When you import an image in black and white it will always import that image into black and transparent white.
When you import an image in color and it has any areas of solid opaque white Decker will use opaque white for that area. That includes any big white background area! If the image has transparent areas, those areas will remain transparent in Decker.
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Because [ Add Outline ] only looks at the 'empty'/transparent white pixels around an image to know where to draw the outline... if there's a big rectangle of opaque white pixels around the image it can't see any 'empty' spaces to draw the outline.
You can fix this inside Decker though! We can just remove the extra white area.
Turn on Transparency Mask with and then select the flood bucket tool. Right click on the opaque white to 'erase' it all back in transparent, clear white. Clean up the edges if you need to and then you should be able to use [Add Outline] around your image like normal.
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I think you were using either a 1-bit logical pattern or an animated pattern for the special outline effect? (Very cool!)
And I think the opaque white issue was why it wasn't working but I also want to talk about another option for a special outline effect if you didn't want to use the black and white 1-bit patterns for the outline effect on your color images.
Because the 1-bit patterns can only use whatever colors are in pattern slots 32 and 47 (which are black and white by default) and neither color can be replaced by another color in the palette.
But you can get a different kind of shifting color effect out of the Animated Patterns!
The way those work is that they cycle through a sequence of other patterns and colors that exist. The default versions only use the 1-bit patterns (for example 1,1,1,1,0,0,0,0 is an animated pattern that blinks between black and white) but absolutely nothing is stopping you from putting things from the 16-color palette in that sequence instead! Maybe blinking between colors or shifting around between them slowly. I dunno!
If this seems interesting to play with here's an editing tool for changing the animated patterns: https://itch.io/post/14641530
Click 'Read' to get the current lists of numbers, change the lists however you want and the click 'Write' to set them and see what you think.
You can copy this canvas into your project to have an easy reference for the numbers for each pattern:
%%WGT0{"w":[{"name":"patternpreview","type":"canvas","size":[103,140],"pos":[138,187],"locked":1,"show":"transparent","border":0,"image":"%%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","scale":1}],"d":{}}
Each animated pattern can have a list of up to 256 other patterns in it... which is mostly useful because you can slow down how quickly it cycles through colors by listing them more than once like 38,38,38,38 instead of just a single 38 which would only be visible for a short moment.
Hopefully something in this helped you!