Summarizing, the main issues encountered with touch- based mobile devices are:  Lack of logical navigation order (not ensuring the content is correctly presented in sequence)  Unsuitable handling of focus  Lack of orientation on the UI  Presence of application or system controls overlapped on the UI. Therefore, the user is forced to randomly explore the screen to find the letters column, search for the letter needed and then search for an author. Moving the focus on that column is difficult because it is not reached by the focus at all. The letters are placed in the middle of the screen in a vertical way. The user has to tap on a letter when searching for an author. Similar difficulties are also encountered when searching for a book. Furthermore, the user encounters some difficulties in recognizing and localizing the main parts of the UI, especially the one containing the book content - to start the reading. The soft-key controls lead to the same kind of problems mentioned above, although in a different operating system. Other examples of misleading soft-keys can be found in the iPad's built-in eBook reader available in the AppStore: iBooks. The presence of these two bars can be misleading because the bar control items are not made accessible by the operating system to the screen reader. Figure 2 shows 2 bars persisting on ePubReader: in the upper part the eBook controls bar and in the bottom the system bar.

2, namely 'ePub Reader', a free app for Android which was tested on two platforms: an Acer Iconia tablet (running Android 3.2.1) and a Samsung Galaxy Nexus smartphone (running Android 4.2, with a better support for accessibility). For instance this problem occurs in the e-book reader shown in Fig. or be fixed on a portion of the screen, typically on the upper and lower edges.

Epubreader