Change Request

It would be nice to have the Framed Current Line option in Notepad++ similar to the ones in Visual Studio or VS Code.

Currently it is achievable with either the FWDataViz plugin OR by running the following command with the PythonScript plugin: editor.setCaretLineFrame.

The result would be something like:
[ The clip below has line wrapping enabled on purpose. It is capturing the related settings line in NPP's config.xml. ]

Preference dialog

In the Notepad++ Preferences dialog, this setting can be handled either with a checkbox or a horizontal slider control ranging between values 0 to 10. If we implement it with a checkbox, an ideal value to use with the SCI_SETCARETLINEFRAME call would be: 2

Mock screenshot with the new checkbox control in Preferences:

Implementation

The current-line-framing feature is achievable via the Scintilla API function SCI_SETCARETLINEFRAME.

The executing code for this new setting would be the last two lines below added inside Notepad_plus.cpp:
[ The first two lines below are pre-existing, and are only indicated here for the location context. ]

...
	_mainEditView.execute(SCI_SETCARETLINEVISIBLE, svp._currentLineHilitingShow);
	_subEditView.execute(SCI_SETCARETLINEVISIBLE, svp._currentLineHilitingShow);

	_mainEditView.execute(SCI_SETCARETLINEFRAME, svp._currentLineFrameWidth);
	_subEditView.execute(SCI_SETCARETLINEFRAME, svp._currentLineFrameWidth);
...

Of course, there will be other minor additions to: Parameters.h, Parameters.cpp, preference.rc, preferenceDlg.cpp, config4zipPackage.xml. Plus, additions to unitTest scripts for functionList and xml. Lastly, this will also impact various translation files.