Ext.Window show() works incorrectly in IE7/8
I'm using Ext.Window to show images from thumbnails. It also contains toolbar with next/prev buttons to browse the images. In FF or Chrome works everything fine.
In IE I encountered two errors:
1) When I click the magnfying glass icon which triggers the functions that creates Ext.Window, nothing happens. On second click, window is finally shown. (debugger gets to the line winThumbnail.show();)
2) Clicking anywhere on the Ext.Window including close button, header or the next/prev arrows, window becomes grey and the whole pages doesn't respond. Looks like some layer covers it.
I have almost the same functionality (functions for generating Ext.Window and it's template to show buttons are exactly the same) on another page and it works even in IE.
Any ideas what could be possibly wrong?
Thanks in advance.