Main guide update problem after guide communication

Hello

Steps Before Problem:

I have 2 guides (Main Guide , Sub Guide)

I open Sub Guide from Main Guide

Then I transfer 2 parameters(a & b) to Main guide from Sub Guide using the following code:

MainFigureHandle = Main;
MainData = guidata(MainFigureHandle);
set(MainData.lbl_x,'String',a);
set(MainData.lbl_y,'String',b);

So my problem is the following .. When I transfer those 2 parameters, panels in Main Guide change place either upward or\& to the right ... Why ? and how can i solve this problem ?

Thank you in advance