Hi,
1. I believe for this purpose using a custom CSS is much more efficient, as the sizing of the items within the input container follows a flexible (display:flex) display property, and the box-sizing does not contain borders within the overflow by default.
After disabling the borders (on the underline theme it is box shadow, you can disable it here) on the back-end, try this custom CSS to apply a border on the input part only:
.asp_m .proinput {
border-width: 0 0 1px 0 !important;
border-style: solid !important;
border-color: #000 !important;
box-sizing: border-box !important;
}This resulted on my end to something like this: https://i.imgur.com/cOPHACw.png
2. Unfortunately as simple as this sounds, it is very complicated programatically. The results box by default is moved to the document body scope, in order to make sure that any other container element, that does not have an ‘auto’ overflow, does not make the results box invisible, by clipping it. Automatically detecting the menu DOM node position without further information is programatically impossible, that is why the input field is the reference for the results container display.
It is however possible to tweak the results potion as well as the width by using custom CSS. To change it’s minimum width, you can use this:
.asp_r {
min-width: 320px !important;
}Just change the width pixel number to your needs.
It is also possible to push the reuslts box vertically, by forcing a top margin to it. In your case a lower value, somewhere around 4 pixels should do the trick:
.asp_r {
margin-top: 4px !important;
}3. I completely agree with a customizer for sure. I am constantly working on all plugin features to make it as simple as possible, but as you can see there are lots of options available, and it is not easy to organize them, especially considering older plugin installation compatibility.
This is the main reason I cannot quickly add a customizer feature, as for new installations it would work, but all the previously installed copies (over 9000) need to work as well, and that transition is very difficult and time consuming. I really hope I can implement such feature in the next upcoming months.
The search on the given URL is completely custom made with very different features. The only way to replicate that is to custom code it, which can be very expensive and could take a lot of time. While tabbed results are not available, you can try the results grouping feature, which allows separating results by criteria.