Problem:

Can not locate the 'text find and replace' window within the IDE window

Resolution:

Click on the View | Dockable Windows menu option within the IDE

and see if the 'text find and replace' window is ticked or not.

If it is not ticked, then tick it.

If it is already ticked then click on the 'Window' menu and select either 'Tile Horizontally' or 'Tile Vertically' or 'Cascade' or 'Tile Docked Windows' or 'Arrange Floating' to locate the floating 'text find and replace' window.

When the 'text find and replace' window is located, right click on the window and tick the option to 'Allow docking'.  Then drag and dock the window to a specific location.