[GUI] Find Characters in Range... dlg accelerators and edit fields

[ozone10]

Description of the Issue

Find Characters in Range... dialog does not have key accelerators for all controls.
Changing values in edit controls have no effect if "My Range" is not selected, this can cause confusion.

Steps to Reproduce the Issue

1ab. Open Find Characters in Range... dialog
2a. Press ALT key to show key accelerators
2b. Change values in edit controls without selecting "My Range"
3b. Press Find button

Expected Behavior

Key accelerators for all controls.
Better handling for edit controls and "My Range"

Actual Behavior

Missing key accelerators.

Debug Information

Notepad++ v8.5.2