[Feature request] Default to transparent backgrounds for User Defined Languages

Author: StevoisiakCreated Sep 17, 2026Updated Sep 17, 2026

Is there an existing issue (open or closed) for this?

I have searched the existing issues

Description of the Issue

When creating a new User Defined language, the background color defaults to white instead of transparent. This doesn't make a difference when using NP++'s default light theme, but it becomes very visible when switching to dark mode.

Describe the solution you'd like.

When creating a new User Defined Language, have the default background color set to Transparent.

Debug Information

bash

Notepad++ v8.9.8   (64-bit)
Build time: Aug 23 2026 - 17:22:44
Scintilla/Lexilla included: 5.6.6/5.5.3
Boost Regex included: 1_90
pugixml included: 1.16
nlohmann JSON included: 3.12.0
Path: C:\Program Files\Notepad++\notepad++.exe
Command Line: "C:\Users\[redacted]\Documents\Coding (alt)\Stevos-AI-Blocklist\GenAI-Blocklist.txt" 
Admin mode: OFF
Local Conf mode: OFF
Cloud Config: OFF
WinGUp: present
disableNppAutoUpdate.xml: absent
Periodic Backup: ON
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 100%
    visible monitors count: 3
    installed Display Class adapters: 
        0000: Description - Intel(R) UHD Graphics 770
        0000: DriverVersion - 32.0.101.7088
        0001: Description - Microsoft Remote Display Adapter
        0001: DriverVersion - 10.0.26100.8737
        0002: Description - Microsoft Remote Display Adapter
        0002: DriverVersion - 10.0.26100.9278
        0003: Description - Microsoft Remote Display Adapter
        0003: DriverVersion - 10.0.26100.9278
    - warning, search has been limited to maximum number of adapter records: 4
OS Name: Windows 11 Pro (64-bit)
OS Version: 25H2
OS Build: 26200.9457
Current ANSI codepage: 1252
Plugins: 
    mimeTools (3.1)
    NppConverter (4.7)
    NppExport (0.4)

Anything else?

No response

Source: notepad-plus-plus/notepad-plus-plus

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