Umberto, You can set the duration of newly created subtitles, in preferences (Alt+C) on the Editing tab.
There are several text boxes that allow you to set the default duration for many objects. Subtitle is one, I have subtitle duration set to 2.9 seconds, works pretty good for most speaking speeds.

As to modifily the subtitle duration after it is created, you can drag the end of the subtitle on the timeline, put your cursor on the border at the end of a subtitle (Expand the timeline to get better resolution), you get a double arrow and can drag the length. Carl312: Windows 10 64-bit 8 GB RAM,AMD Phenom II X4 965 3.4 GHz,ATI Radeon HD 5770 1GB,240GB SSD,two 1TB HDs.

Carl,

The operation you suggested (drag the end of the subtitle on the timeline) resets the subtitle text to the original text "Doppio click per modificare il testo" (double click to modify text, in italian).

So, looks like subtitles cannot be touched without losing the text.

Must try another time but i had this issue for each subtitle i manually entered yesterday, maybe today will go better

Umberto

Added comment.
You can also move the whole subtitle on the timeline by click on it and dragging to a different postion on the time line.

Search Powerdirector help on 'subtitles'.
Check the topic "Syncing Subtitles with Dialogue".

Help is at Director's Chair > Help. Carl312: Windows 10 64-bit 8 GB RAM,AMD Phenom II X4 965 3.4 GHz,ATI Radeon HD 5770 1GB,240GB SSD,two 1TB HDs.

Umberto wrote
The operation you suggested (drag the end of the subtitle on the timeline) resets the subtitle text to the original text "Doppio click per modificare il testo" (double click to modify text, in italian).

So, looks like subtitles cannot be touched without losing the text.

Must try another time but i had this issue for each subtitle i manually entered yesterday, maybe today will go better

If you Click or double click the subtitle on the timeline you do go back to edit the text. (I was wrong about the mouse action). In my PD8 that action does not erase the text in the subtitle, it just opens the subtitle for edit. (You close the edit by clicking somewhere else, such as time area or another subtile). (I think press Enter key will work also).

You place your mouse cursor at the end of the subtitle(On Timeline), pause, wait for the double arrow, then press left mouse button and drag the end of the subtiltle right to increase the time or drag left to decrease the time.

All of these actions I am talking about are on the Timeline not in the subtitle room, however you must be in the subtitle room to work on subtitles. Carl312: Windows 10 64-bit 8 GB RAM,AMD Phenom II X4 965 3.4 GHz,ATI Radeon HD 5770 1GB,240GB SSD,two 1TB HDs.

Well, my fault.

I started modifying the position/duration with the mouse on the timeline with the text editor still in edit mode. In this case the editor resets to previous value.

Looks like i was too lazy to click out of the editor to commit the change

Umberto

That will do it!
Glad you got your problem solved.

Carl312: Windows 10 64-bit 8 GB RAM,AMD Phenom II X4 965 3.4 GHz,ATI Radeon HD 5770 1GB,240GB SSD,two 1TB HDs.