Steps to reproduce:

1. Options->Edit Link Library...
2. Delete all saved links; Yes to confirm.
3. In the URL field, enter default.html
4. Click the Add button, then OK.
5. Open the text editor and enter some text. Highlight the text and press Ctrl+I (or whatever other required steps) to enter the Link editor.
6. In the "Select or enter the URL..." field, click the down-arrow and select the default.html entry from the list. Click OK to save this link.
7. Click the link in the text editor window to open the Link Editor.
8. Change the previous URL to Default.html (Note the changed capitalization). Click OK to save the change. Then Save and close this text window.
9. Open a new text editor window and enter some text, then highlight this text and enter the Link Editor.
10. Use the URL drop-down arrow to locate the Default.html entry in the URL list. Surprise, it is not there. Instead, the original default.html is listed.

This is really irritating if my first entry is Ourcompany.html but it should have been OurCompany.html. Code completion is finding the first erroneous entry and not the 2nd corrected one (since it is never saved).