SUMMARY
Adding words to the Kate spellcheck dictionary does not function correctly. 

STEPS TO REPRODUCE AND OBSERVATIONS
1. Type a word that is not in Kate's dictionary.
2. Right-click on the word to bring up the context menu.
3. Hover over the entry "Spelling" to produce a sub-context menu.
4. Select the "Add to Dictionary" context menu item.
5. The red line under the word disappears, giving the illusion that the word was successfully added to the dictionary. Now type the same word a second time in the same document. This second word will have a red line under it, showing that the word is still not recognized by the dictionary.
6. Press "Control+Shift+," to open the "Configure Kate" window.
7. Navigate to: "Editor Component → Editing → Spellcheck" tab.
8. In the "Ignored Words" section of this tab, you can see that the word you supposedly added to the dictionary is not present in the words listed.
9. Add the word you want the dictionary to ignore from now on and press OK.
10. As you can see both words are now underlined red, showing that a word added to the Spellchecker Ignore Words list does not affect words typed in the document window.


EXPECTED RESULT
1. When a word is added to the dictionary from the right-click context menu, I expect it to be added to the Spellchecker Ignored Words list.
2. I expect that a word added to the Spellchecker Ignored Words list will no longer be underlined in the document window.


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 18.04
KDE Plasma Version: 5.12.9
KDE Frameworks Version: 5.44.0
Qt Version: 5.9.5
Kate is v17.12.3