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/PathVariableDialog.java
dialog.setResource(currentResource);
        if (dialog.open() == IDialogConstants.OK_ID) {
            String[] variableNames = (String[]) dialog.getResult();
            if (variableNames != null && variableNames.length == 1) {
                String newValue = variableNames[0];
            	IPath path = Path.fromPortableString(newValue);
                if (operationMode != EDIT_LINK_LOCATION && currentResource != null && !path.isAbsolute() && path.segmentCount() > 0) {
                	path = PathVariableUtil.buildVariableMacro(path);
                	newValue = path.toPortableString();
                }
                variableValue = newValue;
                variableValueField.setText(newValue);
            }
        }
    }
    /**
     * Adds buttons to this dialog's button bar.
     * 
     * @see org.eclipse.jface.dialogs.Dialog#createButtonsForButtonBar
     */
    protected void createButtonsForButtonBar(Composite parent) {
        okButton = createButton(parent, IDialogConstants.OK_ID,
                IDialogConstants.OK_LABEL, true);
        okButton.setEnabled(type == EXISTING_VARIABLE);
        createButton(parent, IDialogConstants.CANCEL_ID,
                IDialogConstants.CANCEL_LABEL, false);
    }
    /**
     * Validates the current variable name, and updates this dialog's message.
     *