Developer Mode

When editing pages in AEM, several modes are available, including Developer mode. This opens a side panel with several tabs that provide a developer with infomation about the current page. The three tabs are:

Components for viewing sructure and performance information.
Tests for running tests and analyzing the results.
Errors to see any problems occuring.

These help a developer to:

Discover: what pages are composed of.
Debug: what is happening where and when, which in turn helps to resolve issues.
Test: does the application behave as expected.

CAUTION

Developer mode:

Is only available in the touch-enabled UI (when editing pages).
Is not available on mobile devices or small windows on desktop (due to space restrictions).
- This occurs when the width is less than 1024px.
Is only available to users who are members of the administrators group.

CAUTION

Developer mode is only available on a standard author instance that is not using the nosamplecontent run-mode.

If required it can be configured for use:

on an author instance using nosamplecontent run-mode
a publish instance

It should be disabled again after use.

NOTE

See the:

Knowledge Base article, Troubleshooting AEM TouchUI issues, for further tips and tools.
AEM Gems session about AEM 6.0 Developer Mode.

Opening Developer Mode

Developer mode is implemented as a side panel to the page editor. To open the panel, select Developer from the mode selector in the toolbar of the page editor:

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The panel is divided into two tabs:

Components - This shows a component tree, similar to the content tree for authors
Errors - When problems occur, details are shown for each component.

Components

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This shows a component tree that:

Outlines the chain of components and templates rendered on the page (SLY, JSP, etc.). The tree can be expanded to show context within the hierarchy.
Shows the server-side computational time needed to render the component.
Allows you to expand the tree and select specific components within the tree. Selection provides access to component details; such as:
- Repository path
- Links to scripts (accessed in CRXDE Lite)
Selected components (in the content flow, indicated by a blue border) will be highlighted in the content tree (and vice versa).

This can help to:

Determine and compare the rendering time per component.
See and understand the hierarchy.
Understand, and then improve, the page loading time by finding slow components.

Each component entry can show (for example):

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View Details: a link to a list that shows:
- all component scripts used to render the component.
- the repository content path for this specific component.
Edit Script: a link that:
- opens the component script in CRXDE Lite.
Expanding a component entry (arrow head) can also show:
- The hierarchy within the selected component.
- Rendering times for the selected component in isolation, any individual components nested within it, and the combined total.

CAUTION

Some links point to scripts under /libs. However, these are for reference only, you must not edit anything under /libs, as any changes you do make may be lost. This is due to the fact that this branch is liable to changes whenever you upgrade or apply a hotfix/feature pack. Any changes you require should be made under /apps, see Overlays and Overrides.

Errors

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Hopefully the Errors tab will always be empty (as above), but when problems occur the following details are shown for each component:

A warning if the component writes an entry to the error log, together with details of the error and direct links to the appropriate code within CRXDE Lite.
A warning if the component opens an admin session.

For example, in a situation where a undefined method is called, the resulting error will be shown in the Errors tab:

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