Data Browser: Allow 'drop' of PV names into plot on Linux

[kasemir]

On most OS, strings (PV names) can be dropped into the Data Browser plot, opening an "Add PV" dialog for the text, which is presumably a PV name.

On RedHat 6, no "drop" appears to be possible. Need to check drop types to determine why not.

[kasemir]

The behavior under Linux is somewhat irreproducible.

Most of the time, dropping names from a text editor into the Data Browser plot works.

Dropping from EDM on the other hand doesn't.
In the debugger, the 'dragEnter' and 'dragLeave' events are seen, with the correct STRING transfer type, but the 'drop' just doesn't happen. Could be related to the fact that EDM uses the middle mouse button, not the more common left button.
However, when opening the EDM 'PV List' window, typing some text into its 'File' text entry widget, that text can be dragged/dropped using the middle mouse button. And, after that was successful, it is now possible to drag/drop a few PV names from ordinary EDM displays for a while, until it will suddenly stop functioning and a 'drop' is again impossible. So something in the X windows behavior changes for a while when opening the EDM "PV List" window and once dragging a text from there.

[willrogers]

Shall we close this if it's not going to be fixed?

[kasemir]

OK