Bug 298835 Merge e4 Project Path Variable back into the 3.6 stream
The virtual folder and filters changes are already in 3.6, the project path variable changes in e4 still remains to be merged.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/PathVariablesGroup.java
}
        return true;
    }
    /**
     * @param varName
     *            the variable name to test
     */
    private boolean isBuiltInVariable(String varName) {
        if (currentResource != null) {
        	IPathVariable variable = pathVariableManager.getPathVariable(varName, currentResource);
            if (variable != null) 
            	return variable.isReadOnly();
        }
        return false;
    }
    /**
     * Sets the <code>GridData</code> on the specified button to
     * be one that is spaced for the current dialog page units. The
     * method <code>initializeDialogUnits</code> must be called once
     * before calling this method for the first time.
     *
     * @param button the button to set the <code>GridData</code>
     * @return the <code>GridData</code> set on the specified button
     */
    private GridData setButtonLayoutData(Button button) {
        GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
        int widthHint = Dialog.convertHorizontalDLUsToPixels(fontMetrics,
                IDialogConstants.BUTTON_WIDTH);
        data.widthHint = Math.max(widthHint, button.computeSize(SWT.DEFAULT,
                SWT.DEFAULT, true).x);