Version 1.4.2 is out. Download it at the link at the beginning of the top post.
Thanks to @Kumirei who has graciously permitted to reuse some Dashboard Apprentice code in Item Inspector. This came handy in this version and will be useful for some more features that I am planning.
This version is about look and ease of use to make Item Inspector more enjoyable.
First tooltips are renamed popups. Items are not tools so the term tooltip is inappropriate.
Then the look of the popups is improved. See.

Then there is a goodie for those like myself who use the tables to study. The procedure is to go over the items and recite aloud the meaning and reading. Then we use the popup to check the answer. The problem is the items are small and hard to recognize. There is an enlarged version in the popup but consulting this would reveal the meaning and reading before its time. The solution is to have another popup at the right of the item for this purpose. This popup may be annoying for those who don’t use the table for studying. There is a setting to enable or disable it on a table per table basis.

Then there is an issue with Wanikani data that causes some radicals to appear black as below. You may have seen some of those. This is resolved. Now all radicals will show the same color.
Example of the problem:

I have noticed that the Breeze Dark theme changes the height of the lines. This is annoying because Item Inspector is designed to fit the table on one screen to avoid scrolling. Dark Breeze breaks this. A setting has been added to change the number of lines in the table. You may now make the table fit your screen.
A final note to Breeze Dark users. In item Inspector table entries are colored to identify whether an item is radical, kanji or vocabulary. This theme makes all the entries black so this information is lost. This color information is available in the background of popup images, so Breeze Dark users may use that. If there is popular demand from Breeze Dark users to restore the colors in the table I will make an effort.
Coming up next: a data exporter for use with spreadsheet software as per @ekg request.