In order to avoid this problem, i had to set a main View in my app in fixed height value instead of its previous relative value in percentage. For this reason i wrote this formula when creating that main View:
height:loginScrnHeigh/Ti.Platform.displayCaps.logicalDensityFactorloginScrnHeigh is gotten by making some percentage Cross-multiplication (i won't show this calculation here) to determine what should be that value if (9.375 % --- === --> 65 pixels) so (81.25 % --- === --> ??? = loginScrnHeigh).. and the factor logicalDensityFactor was 1,5. i have met also another problem when setting the main height value which is that, by the docuementation : "View height, in platform-specific units." so normally it's not an obligation to put 'px' when setting the value but it wasn't the same result when adding it or not.