These are the logs in debug level after closing preference activity and resuming to preview:
05-29 19:47:42.610: I/jPCT-AE(13608): Unloaded texture: 3
05-29 19:47:42.630: I/jPCT-AE(13608): Visibility lists disposed!
05-29 19:47:42.630: I/jPCT-AE(13608): Unloaded texture: 6
05-29 19:47:42.630: I/jPCT-AE(13608): Unloaded texture: 4
05-29 19:47:42.630: I/jPCT-AE(13608): Unloaded texture: 2
05-29 19:47:42.630: I/jPCT-AE(13608): Unloaded texture: 1
05-29 19:47:42.630: I/jPCT-AE(13608): Unloaded texture: 5
05-29 19:47:42.630: I/jPCT-AE(13608): All texture data unloaded from gpu!
05-29 19:47:42.630: I/jPCT-AE(13608): Disposing VBOs!
05-29 19:47:42.640: I/jPCT-AE(13608): Renderer disposed!
05-29 19:47:42.640: I/jPCT-AE(13608): GLRenderer disposed with id 1 on Thread[GLThread 55676,5,main]
05-29 19:47:42.640: I/jPCT-AE(13608): GLRenderer created with id 2 on Thread[GLThread 55676,5,main]
05-29 19:47:42.645: I/jPCT-AE(13608): OpenGL vendor: ARM
05-29 19:47:42.645: I/jPCT-AE(13608): OpenGL renderer: Mali-400 MP
05-29 19:47:42.645: I/jPCT-AE(13608): OpenGL version: OpenGL ES-CM 1.1
05-29 19:47:42.645: I/jPCT-AE(13608): OpenGL renderer initialized (using 2 texture stages)
05-29 19:47:42.645: I/jPCT-AE(13608): Allocating native memory for 128*128 texture(true/false/false/false/): 65536 bytes!
05-29 19:47:42.650: I/jPCT-AE(13608): New texture's id is: 1
05-29 19:47:42.650: I/jPCT-AE(13608): New texture uploaded: com.threed.jpct.Texture@41f82c48 in thread Thread[GLThread 55676,5,main]
05-29 19:47:42.650: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:42.650: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:42.650: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:42.650: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:42.650: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:42.650: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:42.650: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:42.650: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:42.650: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:42.650: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:42.655: I/jPCT-AE(13608): Allocating native memory for 1024*1024 texture(true/false/false/false/): 4194304 bytes!
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly1'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly2'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly3'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly4'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly5'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly6'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly7'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly8'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly9'
05-29 19:47:42.905: I/jPCT-AE(13608): VBO disposed for object 'firefly10'
05-29 19:47:42.920: I/jPCT-AE(13608): New texture's id is: 2
05-29 19:47:42.940: I/jPCT-AE(13608): New texture uploaded: com.threed.jpct.Texture@41f82fa8 in thread Thread[GLThread 55676,5,main]
05-29 19:47:42.940: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:42.940: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:42.940: I/jPCT-AE(13608): Allocating native memory for 1024*1024 texture(true/false/false/false/): 4194304 bytes!
05-29 19:47:43.165: I/jPCT-AE(13608): New texture's id is: 4
05-29 19:47:43.175: I/jPCT-AE(13608): New texture uploaded: com.threed.jpct.Texture@41f71e68 in thread Thread[GLThread 55676,5,main]
05-29 19:47:43.175: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.175: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.175: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.175: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.175: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.175: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.175: I/jPCT-AE(13608): Allocating native memory for 64*64 texture(true/false/false/false/): 16384 bytes!
05-29 19:47:43.175: I/jPCT-AE(13608): New texture's id is: 5
05-29 19:47:43.175: I/jPCT-AE(13608): New texture uploaded: com.threed.jpct.Texture@41f76910 in thread Thread[GLThread 55676,5,main]
05-29 19:47:43.175: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.175: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.180: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.180: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.180: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.180: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.180: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.180: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.180: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.180: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.180: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.180: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.180: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.180: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.180: I/jPCT-AE(13608): Allocating native memory for 64*64 texture(true/false/false/false/): 16384 bytes!
05-29 19:47:43.185: I/jPCT-AE(13608): New texture's id is: 6
05-29 19:47:43.185: I/jPCT-AE(13608): New texture uploaded: com.threed.jpct.Texture@41f6db30 in thread Thread[GLThread 55676,5,main]
05-29 19:47:43.185: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.185: I/jPCT-AE(13608): Creating buffers...
05-29 19:47:43.185: I/jPCT-AE(13608): OpenGL context has changed(2)...recovering for renderer 2/1!
05-29 19:47:43.185: I/jPCT-AE(13608): Creating buffers...
I also tried without creating the new framebuffer when context changes. The same issue is still there. Surprisingly, I do exactly the same method to other objects and textures, it works fine.