[Feature request] Document Map to occupy a pane with an independent width from other output, such as MarkdownViewer++ plugin Preview

Is there an existing issue for this?

• I have searched the existing issues

Description of the Issue

I routinely use the Document Map as a visual vertical scrollbar, and find it very useful (as is the similar feature in Visual Studio Code). I also make use of the MarkdownViewer++ plugin to preview Markdown files, with its handy Ctrl+Shift+M preview shortcut.

The issue is that that the preview of a Markdown document (as generated by MarkdownViewer++) occupies the same pane as the Document Map. When the pane's width is sized appropriately for the Document Map, that width is too narrow for the Markdown document Preview, and vice versa.

Describe the solution you'd like.

Would it be possible for the width of the Document Map to be independent of the MarkdownViewer++ pane (and other plugins that utilise the side pane)?

For example, if Notepad++ recorded the width of the Document Map as X, and you activate the Markdown preview with Ctrl+Shift+M and resize the width to Y, closing the preview (with Ctrl+Shift+M) could restore the width back to X. Enabling the Markdown preview again could reset the width back to Y.

Thank you!

Debug Information

Notepad++ v8.9.6.4   (64-bit)
Build time: Jun  3 2026 - 23:47:49
Scintilla/Lexilla included: 5.6.2/5.4.9
Boost Regex included: 1_90
pugixml included: 1.15
nlohmann JSON included: 3.12.0
Path: C:\Program Files\Notepad++\notepad++.exe
Command Line: "path-obscured\Lorem Ipsum.md" -multiInst -nosession -lnormal -n1 -c2
Admin mode: OFF
Local Conf mode: OFF
Cloud Config: path-obscured\Notepad++
WinGUp: present
disableNppAutoUpdate.xml: absent
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: ON
Display Info:
    primary monitor: 1920x1080, scaling 125%
    visible monitors count: 3
    installed Display Class adapters: 
        0000: Description - Intel(R) Graphics
        0000: DriverVersion - 31.0.101.5382
        0001: Description - NVIDIA RTX 2000 Ada Generation Laptop GPU
        0001: DriverVersion - 31.0.15.5274
        0002: Description - Microsoft Remote Display Adapter
        0002: DriverVersion - 10.0.26100.7309
        0003: Description - Microsoft Remote Display Adapter
        0003: DriverVersion - 10.0.26100.6725
    - warning, search has been limited to maximum number of adapter records: 4
OS Name: Windows 11 Enterprise (64-bit)
OS Version: 24H2
OS Build: 26100.8655
Current ANSI codepage: 1252
Plugins: 
    CSVLint (0.4.7)
    JSMinNPP (25.11.16)
    MarkdownViewerPlusPlus (0.8.2)
    mimeTools (3.1)
    NppConverter (4.7)
    NppExport (0.4)
    NPPJSONViewer (2.1.1)
    PythonScript (2.1)
    RunMe (1.6.1)
    XMLTools (3.1.1.13)

Anything else?

No response

Start by locating the Document Map and plugin side-pane layout handling in Notepad++. Compare how the two panes currently share width and how each pane is shown or hidden. Done means the Document Map and MarkdownViewer++ preview can retain independent widths and restore their respective sizes when toggled.