The Sony Xperia Z4 Tablet has a neat feature when used with the companion BKB50 Bluetooth Keyboard, it shows a list of recent apps that looks similar to the Windows Start menu. However, what can be annoying is there is a picture of the keyboard that limits how many recent apps can be seen.
Step forward AndroPlus from XDA, who has created a mod that allows you to use the space occupied by the picture for more recent apps. The mod is only confirmed to work with the LTE version (SGP771), but it could work on the Wi-Fi version (SGP712). Your tablet will need to be rooted for the mod to work. The adb instructions can be found at the source link.
Sony Xperia Z4 Tablet Recent Apps Keyboard Launcher – Original
Sony Xperia Z4 Tablet Recent Apps Keyboard Launcher – Using Mod