Window/app switcher highlights hard to see

I agree with these concerns but there are too many different issues here. Can you please put each in a separate bug?

When a bug report lists multiple issues like this it is hard to achieve a definitive fix. It also confuses discussion about each issue.

As a workaround for shades of grey that don't contrast sufficiently you might want to check your monitor's gamma value is *low* enough. Gamma is an exponent but the resulting brightness used is only between the values of 0 and 1 so a *lower* gamma value is what makes low-contrast things easier to see. Typically an accurate gamma value is around 2.2, but some monitors default to higher exponents like 2.4 which makes darker colours unrealistically difficult to see.

Some monitors and TVs will try to make the setting easier to understand by inverting it - higher gamma setting means lower gamma exponent, which at least results in a higher brightness for darker elements.

> When a bug report lists multiple issues like this [...]

Sorry about that. Part of it is, I half expected this to be shot down or ignored anyway.
But the bigger part is that, to my mind, it *is* one single issue. Namely that the person(s) who designed 22.04's iteration of Yaru have excellent eye sight and/or equipment and didn't think of the fact that other people might not. Worse, that the functional side of the visual presentation just doesn't seem to be a consideration. For me, it's bad enough that it could be called an accessibility issue, but having elements of the UI be easily distinguishable reduces eye strain and shortens the time normally-sighted people need to perceive and process information as well, etc. It's not like, say, colour-blind modes, which are detrimental if you don't need them.

These kinds of issues pop up again and again. Somebody complains, it's fixed in the next version, then it gets broken again in the next overhaul, possibly in a different way, rinse, repeat ...

I'll gladly give feedback, and if the best way to do that is to report individual bugs against 22.04 (?), I can do that. But I've no illusions that 22.04 will be fixed, and I suspect that whatever will go into 23.10 and 24.04 will have different issues. Maybe it would be better to focus on 23.10/24.04? Don't know when would be a good time to test drive an alpha/beta so that input can still be considered.

> you might want to check your monitor's gamma value is *low* enough.

Good idea. It's set to sRGB, though, gamma 2.2 included. According to my cheap colorimeter even the factory preset was decent when I got it. I know there's drift, but given that I'm not seeing any other weirdness I think I'm good on that front.

I think this bug should be reworded/simplified to only cover the window switcher and app switcher. That in itself is a difficult design problem because the current highlight seems to be inherited from the shell theme. And we may want to keep it consistent with the highlighting used in the top panel which appears to be the same low contrast greys.

The orange frame in the workspace overview is not meant to be thin and probably doesn't need a bug report at all. It looks like that's just a function of you viewing it at scaling factor 100% which is too low for 3840x2160. Please try changing Settings > Screen Display > Scale = 200%, or try enabling Fractional Scaling for values between 100% and 200%.

> I think this bug should be reworded/simplified to only cover the window switcher and app switcher.

Fine by me. Edited.

> That in itself is a difficult design problem because the current highlight seems to be inherited from the shell theme. And we may want to keep it consistent with the highlighting used in the top panel

What highlighting in the top panel?

FWIW, if you have the Just Perfection extension (https://extensions.gnome.org/extension/3843/just-perfection/), you can have it override some theme stuff via ~/.local/share/gnome-shell/extensions/just-perfection-desktop@just-perfection/stylesheet.css. I have the following in there, and it works perfectly.

.just-perfection .switcher-list .item-box:selected
{
    background-color: #dd4814;
    color: #eeeeec;
}

> The orange frame in the workspace overview is not meant to be thin [because 4K]

The thickness is probably specified in pixels somewhere, which is a bug in itself. How many DPI a monitor has varies widely even between common native resolutions and sizes these days, and high-DPI displays are mainstream now. 32 " at 3840x2160 isn't even particularly high-DPI.

EDIT: found it. Here's a workaround for Just Perfection's stylesheet.css. Not pretty but it works:

.just-perfection .workspace-thumbnail-indicator
{
  border: 10px solid #dd4814;
  border-radius: 3px;
  padding: 0px;
}

> scaling factor 100% [...] is too low for 3840x2160. Please try changing Settings > Screen Display > Scale = 200%, or try enabling Fractional Scaling for values between 100% and 200%.

I've run 18.04 in this configuration (at 100 %) for years. It was fine; none of the UI elements were too small or otherwise too hard to see. I'd rather not waste my precious screen real estate by enabling scaling globally. There's literally no point in running a 4K screen at 200 %, might as well get a 1080p one.
That said, a little bit of scaling would be nice, so I tried the fractional option--but even 125 % is too much for my liking. (I do scale in applications, changing the scale factor dynamically as required.)

> What highlighting in the top panel?

When the mouse hovers over top panel elements you see the same mid grey selection over a dark grey background as the window/app switchers. They're all themed the same so really we're probably talking about changing the colour for all of them.