By default, Windows does not allow copying the text from open Window, but it can be done with freeware and portable tool, GetWindowText. Textify also allows you to copy the text but from Dialog boxes.
How to copy text from open windows with GetWindowText?
If you have a folder or program window open and want to copy the text, you can easily use this freeware GetWindowText tool.
1. Left click from mouse-button on the GetWindowText icon on the left side, and by holding down, it drags on the Window from where you want to read/copy the Text.
2. When you release the mouse button, the reading will be finished. The text will appear in the GetWindowText tool’s textbox, which you can copy by selecting it.
This freeware software can read almost all the texts from Edit, Static, Groupbox Controls, etc. It also supports directory trees (SysTreeView32), Combobox, and list views (SysListView32) to read the entire contents.
GetWindowText is compatible with all Windows versions, including Windows 10 / 8 / 7 / Vista and Windows XP, and supports x64 and x32 operating systems. You can download GetWindowText from here.
JOCR is another useful app that allows you to copy texts from scanned documents in Windows 10/8/7. Gttext is another useful app that lets you copy Error Codes & Messages from Dialog Boxes In Windows 10/8/7.