How to set the minimum width of the Tool Window

I added a JTabbedPane in the Tool Window and set the minimum width of the JTabbedPane, But it did not work.

class InsightsPanel(project: Project) : JTabbedPane() {
    init {
        this.add("Overview", OverviewPanel(project))
        this.add("Hourly", CommitsHourPanel(project))
        this.add("Weekly", CommitsWeekdayPanel(project))
        this.add("Monthly", CommitsMonthPanel(project))
        this.add("Timezone", CommitsTimezonePanel(project))
        this.add("Project Top(N)", CommitsProjectPanel(project))
    }

    override fun getMinimumSize(): Dimension {
        return Dimension(800, 200)
    }
}