Enable theming preference check box is not working as expected and forces to restart twice

[opcoach]

Let's make sure issue is not already fixed in latest builds first.

• I verified I can reproduce this issue against latest Integration Build of Eclipse SDK

Steps to reproduce

From a fresh installation and clean workspace:

Install the setup of 'platform ui' by dragging the setup link in the banner of the installer : see Setting your environment and projects guide

Open the preference dialog and filter on 'theme'. Disable theming if there is one selected by unchecking the 'Enable Theming' checkbox and restart. Eclipse restarts without any theme.

Then reopen the preference dialog and filter on 'theme' then check the 'Enable theming' check box again and click Apply.

Eclipse will ask to restart, while no Theme has been yet selected.. and no theme has been proposed. The possible themes will appear after the restart and will be applicable, but we will have to restart again... this is not straightforward and totally counterintuitive.

Actually, when the 'Enable theming' is selected, it must display the themes and then propose to select one and restart when it is applied (even if the theme was not changed in the combo).

This is the current situation when we switch from 'Enable theming' unchecked to checked:

What we have (unchecked to checked)	What we expect

On the other hand, if we unchecked the theme while it was checked, the list of themes should be hidden:

What we have (checked to unchecked)	What we expect

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The Plugin Spy (Alt Shift F1), launched when the preference page is displayed says that this preference page is managed by the ViewsPreferencePage in the org.eclipse.ui.workbench plugin :

A change event listener could be added on the preference checkbox editor so as to react on the change and display or not the bloc of theme list.

Tested under this environment:

• OS & version: macOS X 15.1 (sequoia).
• Eclipse IDE/Platform version (as shown in Help > About): Version: 2024-12 (4.34) Build id: I20241117-1800 (got from the platform.ui current setup)

Community

• I understand reporting an issue to this OSS project does not mandate anyone to fix it. Other contributors may consider the issue, or not, at their own convenience. The most efficient way to get it fixed is that I fix it myself and contribute it back as a good quality patch to the project.