Description

In Mermaid subgraphs always default to the top-to-down (TD) layout, even if a different global direction (LR, RL, or BT) is explicitly set. This forces users to manually declare directions inside each subgraph, creating redundancy and confusion.

Steps to reproduce

Example 1: Global LR, Subgraph defaults to TD (Incorrect):

mermaid
graph LR
  subgraph ShouldInheritLR ["Should Inherit LR"]
    NodeA --> NodeB
  end

**Expected Behavior:
The subgraph should inherit the global left-to-right (LR) direction implicitly.

**Actual Behavior:
The subgraph incorrectly defaults to top-to-bottom (TD).

Example 2: Explicitly Stated Subgraph Direction (Correct but Redundant):

mermaid
graph LR
  subgraph ExplicitLR ["Explicitly LR"]
    direction LR
    NodeE --> NodeF
  end

**Actual Behavior:
Correctly renders due to explicit declaration, but redundant because global direction was already set to LR.

Screenshots

**Failing Exemple

**Working Exemple

Code Sample

Setup

Environment
Mermaid.js Version: v11.4.1

Browser: Microsoft Edge v132.0.2957.115

OS: Windows 11

Suggested Solutions

No response

Additional Context

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