66441 Next Window is slow

        用户说道：

        In version 16.1, navigation "Next used Window" is extremely slow when there are many open windows. When there is just few, it's fine. Navigation to previous window is always fast. I use ctrl-tab key to navigate to next window.
        I reported this for one of previous versions, and it was improved (although not completely) in one of the following versions. Now it's back to being unbearably slow. I don't understand why is it so difficult to implement it right - why navigation to previous window can be instantaneous, and navigation to next window must take several seconds. This is quite annoying and forcing me to use old version.

        他在这段话里报告了，开了很多窗口后，往前翻和往后翻的的效果差异很大，往前很快，往后非常慢。

        这个问题自然由AA的工程师解决，所以在这里，科普一下plsqldev的两种Document Interface:

1. Multiple Document Interface (MDI)
2. Single Document Interface (SDI) 

        16的手册是这么说的(page 305):

        You can use PL/SQL Developer with a Multiple Document Interface (MDI), where you can view multiple windows at the same time, or with a Single Document Interface (SDI), where the current window always takes up all of the work area.

        关于MDI:

        To use the MDI mode you can disable the Single Document option on the View ribbon, or press the Switch to Multiple Document Interface button on the right of the SDI window tabs (see chapter 35.2). In MDI mode you can view multiple windows at once.

        就是view ribbon那里有一个Single Document的按钮，如下图所示。

        或者在SDI下，按下图所示的那个在右边的按钮。

        To switch between windows you can click on a window, click on an item in the Window List (see chapter 32), or select it from the pulldown list on the View ribbon.   

        关于SDI, 基本上也就是相反的来，to use the SDI mode you can enable the Single Document option on the View ribbon, or maximize thecurrent window. In SDI mode you will always view just one window.To switch between windows you can click on a tab above the window, click on an item in the Window List (see chapter 32), or select it from the pulldown list on the View ribbon.

       

        其实上面漏了一点，就是不论是SDI还是MDI，都存在的上翻下翻的快捷键。这个在用户偏好  23.16 User Interface – Appearance（page.193）里介绍了

• Settings for Multiple Document Interface.

        When using Multiple Document Interface mode (see chapter 35) you can control the amount of information in the window titles. You can control whether the complete file path or just the file name is included in a window if it is associated with a file. You can also control if the window type is included in the title.

•  Show window tabs for Single Document Interface.

        When disabled, no window tabs will be displayed in Single Document Interface mode. In this case you will need to use the Window List (see chapter 32) or the keyboard (Ctrl-Tab and Ctrl-Shift-Tab) to select a window.

需要分清楚的是，对窗口上面的信息，MDI在手册讲window title，SDI就是window tab。为什么要增加那么多实体呢？我不明白。