Already an issue about this feature:
https://github.com/notepad-plus-plus/notepad-plus-plus/issues/17170

The 2 blank tabs known when the feature was committed:
https://github.com/notepad-plus-plus/notepad-plus-plus/issues/11134#issuecomment-1575226268

So then I went to the changelog history: it was an intentional change in v8.5.5: item 18 from that version’s change.log: it was in response to issue #13796.

I was also testing, but you were faster, and you found the change log and related issue. I hadn’t gotten that far yet. I did discover that 8.5.4 sort-of worked (and 8.5.6 didn’t), except that when launching Notepad++ with no command line argument it opened two empty tabs.

Odd that the issue was “fixed” by disabling the option when sessions aren’t restored, rather than the obvious: instead of creating a new, empty tab when no tab already exists (normal behavior), when the box is checked, create a new, empty tab when no new, empty tab already exists.

@ComputerFields:

It looks like this has never worked the way you (or I) would expect it to.

The only suggestion I can make is to raise an Issue if you care enough, and/or become familiar with the Ctrl+N shortcut for when you need it.

I tried portable copies of old versions: With ☑ Always open a new document in addition at startup checkmarked but ☐ Remember current session for next launch not checkmarked, v8.5.4 will properly create new 1 in addition to any command-line argument files. But v8.5.5 and all the newer ones I tried would all only do the additional new 1 if the ☑ Remember current session for next launch is checkmarked as well.

So then I went to the changelog history: it was an intentional change in v8.5.5: item 18 from that version’s change.log: it was in response to issue #13796. Apparently, no one suggested to the developer that it would still be wanted when there were files opened via the command-line (or context menu, etc).

Confirmed. With:
Settings | Preferences… | New Document:
Always open a new document in addition at startup
checked, double-clicking a file in Windows file explorer or right-clicking and selecting Edit with Notepad++ only opens the file, without an extra new document tab. (Edit to add: this is with Backup | Remember current session for next launch not checked.)

I don’t know (yet) which would be last version in which it works as expected, since I don’t normally have that checked.

Notepad++ v8.8.9   (64-bit)
Build time: Dec  8 2025 - 00:04:32
Scintilla/Lexilla included: 5.5.8/5.4.6
Boost Regex included: 1_85
Path: C:\Program Files\Notepad++\notepad++.exe
Command Line: "D:\Quick\Mask.1985.Director's.Cut.BluRay.1080p.REMUX.AVC.DTS-HD.MA.5.1-LEGi0N.mkv\org.txt" 
Admin mode: OFF
Local Conf mode: OFF
Cloud Config: OFF
Periodic Backup: OFF
Placeholders: OFF
Scintilla Rendering Mode: SC_TECHNOLOGY_DIRECTWRITE (1)
Multi-instance Mode: monoInst
asNotepad: OFF
File Status Auto-Detection: cdEnabledNew (for current file/tab only)
Dark Mode: OFF
Display Info:
    primary monitor: 1920x1080, scaling 100%
    visible monitors count: 1
    installed Display Class adapters: 
        0000: Description - NVIDIA GeForce RTX 2060 SUPER
        0000: DriverVersion - 32.0.15.6094
        0001: Description - Microsoft Remote Display Adapter
        0001: DriverVersion - 10.0.19041.5794
        0003: Description - Microsoft Remote Display Adapter
        0003: DriverVersion - 10.0.19041.5794
        0004: Description - Microsoft Remote Display Adapter
        0004: DriverVersion - 10.0.19041.5794
    - warning, search has been limited to maximum number of adapter records: 4
OS Name: Windows 10 Pro (64-bit)
OS Version: 22H2
OS Build: 19045.6575
Current ANSI codepage: 65001
Plugins: 
    ColumnsPlusPlus (1.3)
    ComparePlus (2.2)
    Compose (1.1)
    ConfigUpdater (2.4)
    ControlledAutoIndent (1.1)
    DSpellCheck (1.5)
    mimeTools (3.1)
    new16 (1)
    NppConverter (4.7)
    NppExport (0.4)
    PythonScript (2.1)
    Unicode Normalize (1.1)

In my 8.8.8 I have “always open a new document in addition at startup” as a setting under Settings/Preferences/New Document. Is this what you are referring to?

Terry

PS, according to the online manual it is
“Notepad++ will always open a new blank document when you start Notepad++, in addition to any active session or files from the command-line (new to v8.5.4)”