Noticed this while reviewing #13529, but it's also in master @ 5ba77df. On macOS 10.13.6:

<img width="209" alt="schermafbeelding 2018-08-01 om 16 22 09" src="https://user-images.githubusercontent.com/10217/43527498-0f571db4-95a7-11e8-8d90-7863947a7689.png">


<img width="178" alt="schermafbeelding 2018-08-01 om 16 12 51" src="https://user-images.githubusercontent.com/10217/43526994-c9a515ec-95a5-11e8-96b8-9e2513e9aac5.png">

* `Show` in the action menu doesn't work if the app was hidden by `Command + H`, it does work when hidden through this menu
* send and receive don't unhide the window when opened for the action menu. It does navigate to the right tab. The other actions do work (sign, verify & debug window)

Clicking "Toon" (= macOS native show) does work, suggesting the GUI uses some non-native method of hiding.
{
        Q_OBJECT
    public:
        explicit ToolTipToRichTextFilter(int size_threshold, QObject *parent = 0);
    protected:
        bool eventFilter(QObject *obj, QEvent *evt);
    private:
        int size_threshold;
    };
    /**
     * Makes a QTableView last column feel as if it was being resized from its left border.
     * Also makes sure the column widths are never larger than the table's viewport.
     * In Qt, all columns are resizable from the right, but it's not intuitive resizing the last column from the right.
     * Usually our second to last columns behave as if stretched, and when on stretch mode, columns aren't resizable
     * interactively or programmatically.
     *
     * This helper object takes care of this issue.
     *
     */
    class TableViewLastColumnResizingFixer: public QObject