Description of the Issue

When the shortcut mapper view is filtered, it doesn't display a keystroke conflict correctly. (See this Community post for context)

Steps to Reproduce the Issue

1. Have a conflict with one of the plugin shortcuts. In my example, both Main Menu [3]: Explorer and Plugin Commands: NppExec.dll Execute... were mapped to F6
2. In Shortcut Mapper, on the Plugin commands tab, scroll normally to Execute... and see it's red, and the message box shows Main menu | 3 Explorer ( F6 ). This is expected behavior.
3. Filter by Execute, then click on one of the others (like "save all files on execute") then back on the red-highligted Execute... row: the message box now shows No shortcut conflicts for this item., even though there is still a conflict, and it's properly highlighted red.

Expected Behavior

Showing Main menu | 3 Explorer ( F6 ) whether the filter is applied or not

Actual Behavior

Correctly shows Main menu | 3 Explorer ( F6 ) when no filter applied, but claims No shortcut conflicts for this item. when there is a filter applied

Debug Information

Notepad++ v7.6.3   (64-bit)
Build time : Jan 27 2019 - 17:16:47
Path : C:\usr\local\apps\notepad++\notepad++.exe
Admin mode : OFF
Local Conf mode : ON
OS : Windows 10 (64-bit)
Plugins : ComparePlugin.dll DSpellCheck.dll MarkdownViewerPlusPlus.dll mimeTools.dll NppConverter.dll NppExec.dll NppFTP.dll PythonScript.dll XMLTools.dll