<font face="Arial, Verdana">First thing I said is using latest dev version. You are apperently using 0.92.x as there is no DisplayList.h and the contents is in ui.h for that version.</font>
Looking into dev version I even saw a entry for megatronics3 for the GLCD Display:
<font face="Arial, Verdana">#elif MOTHERBOARD == 703 // Megatronics v3.0</font>
<font face="Arial, Verdana">
</font>
<font face="Arial, Verdana">#define UI_DISPLAY_RS_PIN 32</font>
<font face="Arial, Verdana">#define UI_DISPLAY_RW_PIN -1</font>
<font face="Arial, Verdana">#define UI_DISPLAY_ENABLE_PIN 31</font>
<font face="Arial, Verdana">#define UI_DISPLAY_D0_PIN -1</font>
<font face="Arial, Verdana">#define UI_DISPLAY_D1_PIN -1</font>
<font face="Arial, Verdana">#define UI_DISPLAY_D2_PIN -1</font>
<font face="Arial, Verdana">#define UI_DISPLAY_D3_PIN -1</font>
<font face="Arial, Verdana">#define UI_DISPLAY_D4_PIN 14</font>
<font face="Arial, Verdana">#define UI_DISPLAY_D5_PIN 30</font>
<font face="Arial, Verdana">#define UI_DISPLAY_D6_PIN 39</font>
<font face="Arial, Verdana">#define UI_DISPLAY_D7_PIN 15</font>
<font face="Arial, Verdana">#define UI_ENCODER_A 45</font>
<font face="Arial, Verdana">#define UI_ENCODER_B 44</font>
<font face="Arial, Verdana">#define UI_ENCODER_CLICK 33</font>
<font face="Arial, Verdana">#define UI_INVERT_MENU_DIRECTION 1</font>
<font face="Arial, Verdana">#define UI_RESET_PIN -1</font>
<font face="Arial, Verdana">
</font>
<font face="Arial, Verdana">so maybe it even works out of the box also some pins seem different.</font>