provider.getCompletions() returns null if RSyntaxTextArea contains a word without space right after

[cengizeken]

Description
I try to use your RSyntaxTextArea and define 7 shorthands. The goal is, if shorthands exist, do nothing, if not, add new shorthand. i.e, I want to create unique shorthands. If I try to add duplicate shorthand, when there are any word, not in the shorthand list, having no space right after, inside RSyntaxTextArea, duplication occurs, but when there is a space right after the word, it behaves as expected.

Steps to Reproduce
Specific steps to reproduce the behavior:

1. Run the main code I provided
2. Click the button "ekle", click CTRL + Space to see the summary and description window. Here you will see 7 shorthands
3. Press x, and click "ekle" button. Then press space, and CTRL + Space, now you will see 8 shorthands, one is duplicate
4. if you repeat step 3, you will have many duplicate shorthands.
5. In step3, if you press x and space, and click "ekle" button. Then press space, and CTRL + Space, now you will see 7 shorthands, no duplicate

Expected behavior
No duplicate shorthands

Actual behavior
Duplicate shorthands as in my case

Screenshots
Add a screenshot if it helps explain the problem.

Java version
java 21.0.1 2023-10-17 LTS
Java(TM) SE Runtime Environment (build 21.0.1+12-LTS-29)
Java HotSpot(TM) 64-Bit Server VM (build 21.0.1+12-LTS-29, mixed mode, sharing)

Additional context
I will add my complete code
NonDuplicateShorthandQuestion.zip