Curious behavior when opening filetypes with an import dialog box

Note: I am running Rhino 6 on Windows 10 Pro (64-bit), but I have noticed this issue on previous versions of both.

Problem: When opening .STL, .STEP, or .OBJ files (the only filetypes I have tested), the Rhino splash screen appears, but then the main viewport window and import dialog box appear beneath the Explorer window from which the file was launched. When the Explorer window is maximized, Rhino seemingly disappears after the splash screen closes.

Other observations:

  • Rhino is not starting minimized, as shrinking, closing, or minimizing the Explorer window reveals Rhino waiting just behind it
  • The Explorer window is momentarily deactivated while the splash screen is visible, but is reactivated (within 1-3 seconds) after it disappears
  • Rhino icon in taskbar glows orange
  • In a 2-monitor setup, the import dialog box for .STEP and .STL files appear to open on the last monitor that it (the dialog box) was used on, regardless of which monitor the main Rhino window opens on (annoying)
  • Only the OBJ import dialog box always appears in front of the main viewport window
  • Native (.3DM) files are NOT affected by this issue, and reliably open in the foreground

Any help here is appreciated!

Hi Zack - I see this, thanks. It looks like clicking in the Rhino viewport restores the order of things, but I’ll see if we can tune this up.


Thanks, Pascal! Also, is there a way to have the options always appear centered over Rhino? It’s a lesser annoyance, but does seem like unintended behavior. As I noted in the OP, “monitor memory” doesn’t seem to happen with the OBJ dialog boxes.

Hello - it seems the behavior here is pretty inconsistent - I see what you describe and others do not, so far but they have one monitor not two, and I have two… I do not know yet if this is really something that can be fixed reliably but a bigger brain will have a look. BTW, does Rhino correctly move in front of Explorer if you just click on the winow? I assume it does, just making sure since it would really be a nuisance if it does not…

As for the dialog location, there’s no option that I know of to control the locations.


I just checked–Rhino does move in front of Explorer when clicked on.

From what I can tell (at least for .STEP and .STL), both the main Rhino window and the dialog boxes remember which monitor they were last used on, but independently from each other.


  1. Open .STEP file, dialog box appears on monitor #1
  2. Drag dialog box to monitor #2, then click OK
  3. Close, then re-open .STEP file. The dialog box now appears on monitor #2