Since I develop Joomla extensions only for my own use, and then make them available if it seems that others might find them useful, I only test compatibility with Browsers and Server configurations that I actually use.
Currently I am only mostly using the Edge browser on Linux (Ubuntu 20.0.4) and Android mobile devices - so I make no attempt to check how things look with other browsers - if something looks wrong to you then by all means send me details and I'll look into correcting it dreckly.
Similarly all websites I manage are running on Ubuntu 20.0.4 and using Apache, MariaDB, and PHP 7.4. For Joomla extensions I am only bothering with Joomla 3.9/10 and making no attempt to check earlier versions and have no plans to switch to Joomla 4 anytime soon. In fact I currently anticipate never switching any existing site to J4 (what would be the point - if it ain't broke don't fix it) and will only use J4 for any new site if someone pays me to.
Back in the days of Joomla 1.5 there used to be Toolbar functions to add spacing
JToolbar::spacer('20px'); and a divider
Jtoolbar::divider(); in between toolbar buttons.
Unfortunately sometime around Joomla 3.6 these functions were disabled - they still exist but now do nothing. But it is still useful to provide some visual grouping of toolbar buttons, for example to separate the buttons for New and Edit from those that do specific actions like change state. This is especially true now that screens have got wider and most people managing websites are probably using a screen width greater than 1024 pixels.
Two ways to do this, both involving CSS tweaks.
For the xbCulture components I have the ability to rate an item (film or book etc) with a number of stars (or other symbols). Personally I have long kept paper, and later spreadsheet lists of films I have seen and given them a rating. Initially I was using a 5 point scale, but I used to find this a bit coarse - I would often want to use a half point to fit something between the ok (3 star) and good (4 star) categories.
If you want to have a tagging facility for items in a component then it is a good idea to use the inbuilt Joomla tagging system. This does quite a lot of the heavy lifting for you (once you have set things up) and has the big advantage that tags can be shared across components. So if you wish to, you can have tags that can be applied both to articles and to items in your component, which saves having to maintain duplicate lists of tags.
You may come across some limitations in the functionality, especially when it comes to filtering a list of items by tag - but that will be a separate post.
This article is to remind me of the various hoops and enhancements needed to get tagging working in xbBooks
Page 5 of 10