Multi window minimize

I can´t minimize a second window created in a plain phbuilder project.

My application have 2 windows: base window and test window, created with
window control page from menu.

All flags of test window are identical as base window´s flags in rescource
manager. Notify, Managment and borders.

The test window is initialiazided in start up module.

I can see all mini-icons in the up bar like of those 2 windows: collapse,
minimize, maximize, restore and close.

All these funcions runs normaly except minimize.

Will be my test window able to stay in hide state and be in the task bar
like base window ?